| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( 𝑥  ·s  𝑦 )  =  ( 𝑥𝑂  ·s  𝑦 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( 𝑦  ·s  𝑥 )  =  ( 𝑦  ·s  𝑥𝑂 ) )  | 
						
						
							| 3 | 
							
								1 2
							 | 
							eqeq12d | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( ( 𝑥  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥 )  ↔  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 ) ) )  | 
						
						
							| 4 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦  =  𝑦𝑂  →  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑥𝑂  ·s  𝑦𝑂 ) )  | 
						
						
							| 5 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦  =  𝑦𝑂  →  ( 𝑦  ·s  𝑥𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 6 | 
							
								4 5
							 | 
							eqeq12d | 
							⊢ ( 𝑦  =  𝑦𝑂  →  ( ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ↔  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) ) )  | 
						
						
							| 7 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑥𝑂  ·s  𝑦𝑂 ) )  | 
						
						
							| 8 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( 𝑦𝑂  ·s  𝑥 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 9 | 
							
								7 8
							 | 
							eqeq12d | 
							⊢ ( 𝑥  =  𝑥𝑂  →  ( ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 )  ↔  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) ) )  | 
						
						
							| 10 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥  =  𝐴  →  ( 𝑥  ·s  𝑦 )  =  ( 𝐴  ·s  𝑦 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥  =  𝐴  →  ( 𝑦  ·s  𝑥 )  =  ( 𝑦  ·s  𝐴 ) )  | 
						
						
							| 12 | 
							
								10 11
							 | 
							eqeq12d | 
							⊢ ( 𝑥  =  𝐴  →  ( ( 𝑥  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥 )  ↔  ( 𝐴  ·s  𝑦 )  =  ( 𝑦  ·s  𝐴 ) ) )  | 
						
						
							| 13 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦  =  𝐵  →  ( 𝐴  ·s  𝑦 )  =  ( 𝐴  ·s  𝐵 ) )  | 
						
						
							| 14 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦  =  𝐵  →  ( 𝑦  ·s  𝐴 )  =  ( 𝐵  ·s  𝐴 ) )  | 
						
						
							| 15 | 
							
								13 14
							 | 
							eqeq12d | 
							⊢ ( 𝑦  =  𝐵  →  ( ( 𝐴  ·s  𝑦 )  =  ( 𝑦  ·s  𝐴 )  ↔  ( 𝐴  ·s  𝐵 )  =  ( 𝐵  ·s  𝐴 ) ) )  | 
						
						
							| 16 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑝  ·s  𝑦 ) )  | 
						
						
							| 17 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( 𝑦  ·s  𝑥𝑂 )  =  ( 𝑦  ·s  𝑝 ) )  | 
						
						
							| 18 | 
							
								16 17
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ↔  ( 𝑝  ·s  𝑦 )  =  ( 𝑦  ·s  𝑝 ) ) )  | 
						
						
							| 19 | 
							
								
							 | 
							simplr2 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 ) )  | 
						
						
							| 20 | 
							
								
							 | 
							simprl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑝  ∈  (  L  ‘ 𝑥 ) )  | 
						
						
							| 21 | 
							
								
							 | 
							elun1 | 
							⊢ ( 𝑝  ∈  (  L  ‘ 𝑥 )  →  𝑝  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 22 | 
							
								20 21
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑝  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 23 | 
							
								18 19 22
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑝  ·s  𝑦 )  =  ( 𝑦  ·s  𝑝 ) )  | 
						
						
							| 24 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑥  ·s  𝑞 ) )  | 
						
						
							| 25 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( 𝑦𝑂  ·s  𝑥 )  =  ( 𝑞  ·s  𝑥 ) )  | 
						
						
							| 26 | 
							
								24 25
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 )  ↔  ( 𝑥  ·s  𝑞 )  =  ( 𝑞  ·s  𝑥 ) ) )  | 
						
						
							| 27 | 
							
								
							 | 
							simplr3 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) )  | 
						
						
							| 28 | 
							
								
							 | 
							simprr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑞  ∈  (  L  ‘ 𝑦 ) )  | 
						
						
							| 29 | 
							
								
							 | 
							elun1 | 
							⊢ ( 𝑞  ∈  (  L  ‘ 𝑦 )  →  𝑞  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 30 | 
							
								28 29
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑞  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 31 | 
							
								26 27 30
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑥  ·s  𝑞 )  =  ( 𝑞  ·s  𝑥 ) )  | 
						
						
							| 32 | 
							
								23 31
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  =  ( ( 𝑦  ·s  𝑝 )  +s  ( 𝑞  ·s  𝑥 ) ) )  | 
						
						
							| 33 | 
							
								
							 | 
							simpllr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑦  ∈   No  )  | 
						
						
							| 34 | 
							
								
							 | 
							leftssno | 
							⊢ (  L  ‘ 𝑥 )  ⊆   No   | 
						
						
							| 35 | 
							
								34 20
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑝  ∈   No  )  | 
						
						
							| 36 | 
							
								33 35
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑦  ·s  𝑝 )  ∈   No  )  | 
						
						
							| 37 | 
							
								
							 | 
							leftssno | 
							⊢ (  L  ‘ 𝑦 )  ⊆   No   | 
						
						
							| 38 | 
							
								37 28
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑞  ∈   No  )  | 
						
						
							| 39 | 
							
								
							 | 
							simplll | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑥  ∈   No  )  | 
						
						
							| 40 | 
							
								38 39
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑞  ·s  𝑥 )  ∈   No  )  | 
						
						
							| 41 | 
							
								36 40
							 | 
							addscomd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑦  ·s  𝑝 )  +s  ( 𝑞  ·s  𝑥 ) )  =  ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) ) )  | 
						
						
							| 42 | 
							
								32 41
							 | 
							eqtrd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  =  ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) ) )  | 
						
						
							| 43 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑝  ·s  𝑦𝑂 ) )  | 
						
						
							| 44 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( 𝑦𝑂  ·s  𝑥𝑂 )  =  ( 𝑦𝑂  ·s  𝑝 ) )  | 
						
						
							| 45 | 
							
								43 44
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑝  →  ( ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ↔  ( 𝑝  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑝 ) ) )  | 
						
						
							| 46 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( 𝑝  ·s  𝑦𝑂 )  =  ( 𝑝  ·s  𝑞 ) )  | 
						
						
							| 47 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( 𝑦𝑂  ·s  𝑝 )  =  ( 𝑞  ·s  𝑝 ) )  | 
						
						
							| 48 | 
							
								46 47
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑞  →  ( ( 𝑝  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑝 )  ↔  ( 𝑝  ·s  𝑞 )  =  ( 𝑞  ·s  𝑝 ) ) )  | 
						
						
							| 49 | 
							
								
							 | 
							simplr1 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 50 | 
							
								45 48 49 22 30
							 | 
							rspc2dv | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑝  ·s  𝑞 )  =  ( 𝑞  ·s  𝑝 ) )  | 
						
						
							| 51 | 
							
								42 50
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) )  | 
						
						
							| 52 | 
							
								51
							 | 
							eqeq2d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑝  ∈  (  L  ‘ 𝑥 )  ∧  𝑞  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  ↔  𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) ) )  | 
						
						
							| 53 | 
							
								52
							 | 
							2rexbidva | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  ↔  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) ) )  | 
						
						
							| 54 | 
							
								
							 | 
							rexcom | 
							⊢ ( ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) )  ↔  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) )  | 
						
						
							| 55 | 
							
								53 54
							 | 
							bitrdi | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  ↔  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) ) )  | 
						
						
							| 56 | 
							
								55
							 | 
							abbidv | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  =  { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) } )  | 
						
						
							| 57 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑟  ·s  𝑦 ) )  | 
						
						
							| 58 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( 𝑦  ·s  𝑥𝑂 )  =  ( 𝑦  ·s  𝑟 ) )  | 
						
						
							| 59 | 
							
								57 58
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ↔  ( 𝑟  ·s  𝑦 )  =  ( 𝑦  ·s  𝑟 ) ) )  | 
						
						
							| 60 | 
							
								
							 | 
							simplr2 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 ) )  | 
						
						
							| 61 | 
							
								
							 | 
							simprl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑟  ∈  (  R  ‘ 𝑥 ) )  | 
						
						
							| 62 | 
							
								
							 | 
							elun2 | 
							⊢ ( 𝑟  ∈  (  R  ‘ 𝑥 )  →  𝑟  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 63 | 
							
								61 62
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑟  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 64 | 
							
								59 60 63
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑟  ·s  𝑦 )  =  ( 𝑦  ·s  𝑟 ) )  | 
						
						
							| 65 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑥  ·s  𝑠 ) )  | 
						
						
							| 66 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( 𝑦𝑂  ·s  𝑥 )  =  ( 𝑠  ·s  𝑥 ) )  | 
						
						
							| 67 | 
							
								65 66
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 )  ↔  ( 𝑥  ·s  𝑠 )  =  ( 𝑠  ·s  𝑥 ) ) )  | 
						
						
							| 68 | 
							
								
							 | 
							simplr3 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) )  | 
						
						
							| 69 | 
							
								
							 | 
							simprr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑠  ∈  (  R  ‘ 𝑦 ) )  | 
						
						
							| 70 | 
							
								
							 | 
							elun2 | 
							⊢ ( 𝑠  ∈  (  R  ‘ 𝑦 )  →  𝑠  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 71 | 
							
								69 70
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑠  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 72 | 
							
								67 68 71
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑥  ·s  𝑠 )  =  ( 𝑠  ·s  𝑥 ) )  | 
						
						
							| 73 | 
							
								64 72
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  =  ( ( 𝑦  ·s  𝑟 )  +s  ( 𝑠  ·s  𝑥 ) ) )  | 
						
						
							| 74 | 
							
								
							 | 
							simpllr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑦  ∈   No  )  | 
						
						
							| 75 | 
							
								
							 | 
							rightssno | 
							⊢ (  R  ‘ 𝑥 )  ⊆   No   | 
						
						
							| 76 | 
							
								75 61
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑟  ∈   No  )  | 
						
						
							| 77 | 
							
								74 76
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑦  ·s  𝑟 )  ∈   No  )  | 
						
						
							| 78 | 
							
								
							 | 
							rightssno | 
							⊢ (  R  ‘ 𝑦 )  ⊆   No   | 
						
						
							| 79 | 
							
								78 69
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑠  ∈   No  )  | 
						
						
							| 80 | 
							
								
							 | 
							simplll | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑥  ∈   No  )  | 
						
						
							| 81 | 
							
								79 80
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑠  ·s  𝑥 )  ∈   No  )  | 
						
						
							| 82 | 
							
								77 81
							 | 
							addscomd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑦  ·s  𝑟 )  +s  ( 𝑠  ·s  𝑥 ) )  =  ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) ) )  | 
						
						
							| 83 | 
							
								73 82
							 | 
							eqtrd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  =  ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) ) )  | 
						
						
							| 84 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑟  ·s  𝑦𝑂 ) )  | 
						
						
							| 85 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( 𝑦𝑂  ·s  𝑥𝑂 )  =  ( 𝑦𝑂  ·s  𝑟 ) )  | 
						
						
							| 86 | 
							
								84 85
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑟  →  ( ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ↔  ( 𝑟  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑟 ) ) )  | 
						
						
							| 87 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( 𝑟  ·s  𝑦𝑂 )  =  ( 𝑟  ·s  𝑠 ) )  | 
						
						
							| 88 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( 𝑦𝑂  ·s  𝑟 )  =  ( 𝑠  ·s  𝑟 ) )  | 
						
						
							| 89 | 
							
								87 88
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑠  →  ( ( 𝑟  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑟 )  ↔  ( 𝑟  ·s  𝑠 )  =  ( 𝑠  ·s  𝑟 ) ) )  | 
						
						
							| 90 | 
							
								
							 | 
							simplr1 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 91 | 
							
								86 89 90 63 71
							 | 
							rspc2dv | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑟  ·s  𝑠 )  =  ( 𝑠  ·s  𝑟 ) )  | 
						
						
							| 92 | 
							
								83 91
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) )  | 
						
						
							| 93 | 
							
								92
							 | 
							eqeq2d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑟  ∈  (  R  ‘ 𝑥 )  ∧  𝑠  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  ↔  𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) ) )  | 
						
						
							| 94 | 
							
								93
							 | 
							2rexbidva | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  ↔  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) ) )  | 
						
						
							| 95 | 
							
								
							 | 
							rexcom | 
							⊢ ( ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) )  ↔  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) )  | 
						
						
							| 96 | 
							
								94 95
							 | 
							bitrdi | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  ↔  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) ) )  | 
						
						
							| 97 | 
							
								96
							 | 
							abbidv | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) }  =  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } )  | 
						
						
							| 98 | 
							
								56 97
							 | 
							uneq12d | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  =  ( { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } ) )  | 
						
						
							| 99 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑡  ·s  𝑦 ) )  | 
						
						
							| 100 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( 𝑦  ·s  𝑥𝑂 )  =  ( 𝑦  ·s  𝑡 ) )  | 
						
						
							| 101 | 
							
								99 100
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ↔  ( 𝑡  ·s  𝑦 )  =  ( 𝑦  ·s  𝑡 ) ) )  | 
						
						
							| 102 | 
							
								
							 | 
							simplr2 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 ) )  | 
						
						
							| 103 | 
							
								
							 | 
							simprl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑡  ∈  (  L  ‘ 𝑥 ) )  | 
						
						
							| 104 | 
							
								
							 | 
							elun1 | 
							⊢ ( 𝑡  ∈  (  L  ‘ 𝑥 )  →  𝑡  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 105 | 
							
								103 104
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑡  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 106 | 
							
								101 102 105
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑡  ·s  𝑦 )  =  ( 𝑦  ·s  𝑡 ) )  | 
						
						
							| 107 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑥  ·s  𝑢 ) )  | 
						
						
							| 108 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( 𝑦𝑂  ·s  𝑥 )  =  ( 𝑢  ·s  𝑥 ) )  | 
						
						
							| 109 | 
							
								107 108
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 )  ↔  ( 𝑥  ·s  𝑢 )  =  ( 𝑢  ·s  𝑥 ) ) )  | 
						
						
							| 110 | 
							
								
							 | 
							simplr3 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) )  | 
						
						
							| 111 | 
							
								
							 | 
							simprr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑢  ∈  (  R  ‘ 𝑦 ) )  | 
						
						
							| 112 | 
							
								
							 | 
							elun2 | 
							⊢ ( 𝑢  ∈  (  R  ‘ 𝑦 )  →  𝑢  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 113 | 
							
								111 112
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑢  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 114 | 
							
								109 110 113
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑥  ·s  𝑢 )  =  ( 𝑢  ·s  𝑥 ) )  | 
						
						
							| 115 | 
							
								106 114
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  =  ( ( 𝑦  ·s  𝑡 )  +s  ( 𝑢  ·s  𝑥 ) ) )  | 
						
						
							| 116 | 
							
								
							 | 
							simpllr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑦  ∈   No  )  | 
						
						
							| 117 | 
							
								34 103
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑡  ∈   No  )  | 
						
						
							| 118 | 
							
								116 117
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑦  ·s  𝑡 )  ∈   No  )  | 
						
						
							| 119 | 
							
								78 111
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑢  ∈   No  )  | 
						
						
							| 120 | 
							
								
							 | 
							simplll | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  𝑥  ∈   No  )  | 
						
						
							| 121 | 
							
								119 120
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑢  ·s  𝑥 )  ∈   No  )  | 
						
						
							| 122 | 
							
								118 121
							 | 
							addscomd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑦  ·s  𝑡 )  +s  ( 𝑢  ·s  𝑥 ) )  =  ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) ) )  | 
						
						
							| 123 | 
							
								115 122
							 | 
							eqtrd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  =  ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) ) )  | 
						
						
							| 124 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑡  ·s  𝑦𝑂 ) )  | 
						
						
							| 125 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( 𝑦𝑂  ·s  𝑥𝑂 )  =  ( 𝑦𝑂  ·s  𝑡 ) )  | 
						
						
							| 126 | 
							
								124 125
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑡  →  ( ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ↔  ( 𝑡  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑡 ) ) )  | 
						
						
							| 127 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( 𝑡  ·s  𝑦𝑂 )  =  ( 𝑡  ·s  𝑢 ) )  | 
						
						
							| 128 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( 𝑦𝑂  ·s  𝑡 )  =  ( 𝑢  ·s  𝑡 ) )  | 
						
						
							| 129 | 
							
								127 128
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑢  →  ( ( 𝑡  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑡 )  ↔  ( 𝑡  ·s  𝑢 )  =  ( 𝑢  ·s  𝑡 ) ) )  | 
						
						
							| 130 | 
							
								
							 | 
							simplr1 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 131 | 
							
								126 129 130 105 113
							 | 
							rspc2dv | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑡  ·s  𝑢 )  =  ( 𝑢  ·s  𝑡 ) )  | 
						
						
							| 132 | 
							
								123 131
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) )  | 
						
						
							| 133 | 
							
								132
							 | 
							eqeq2d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑡  ∈  (  L  ‘ 𝑥 )  ∧  𝑢  ∈  (  R  ‘ 𝑦 ) ) )  →  ( 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  ↔  𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) ) )  | 
						
						
							| 134 | 
							
								133
							 | 
							2rexbidva | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  ↔  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) ) )  | 
						
						
							| 135 | 
							
								
							 | 
							rexcom | 
							⊢ ( ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) )  ↔  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) )  | 
						
						
							| 136 | 
							
								134 135
							 | 
							bitrdi | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  ↔  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) ) )  | 
						
						
							| 137 | 
							
								136
							 | 
							abbidv | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  =  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } )  | 
						
						
							| 138 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑣  ·s  𝑦 ) )  | 
						
						
							| 139 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( 𝑦  ·s  𝑥𝑂 )  =  ( 𝑦  ·s  𝑣 ) )  | 
						
						
							| 140 | 
							
								138 139
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ↔  ( 𝑣  ·s  𝑦 )  =  ( 𝑦  ·s  𝑣 ) ) )  | 
						
						
							| 141 | 
							
								
							 | 
							simplr2 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 ) )  | 
						
						
							| 142 | 
							
								
							 | 
							simprl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑣  ∈  (  R  ‘ 𝑥 ) )  | 
						
						
							| 143 | 
							
								
							 | 
							elun2 | 
							⊢ ( 𝑣  ∈  (  R  ‘ 𝑥 )  →  𝑣  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 144 | 
							
								142 143
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑣  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) )  | 
						
						
							| 145 | 
							
								140 141 144
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑣  ·s  𝑦 )  =  ( 𝑦  ·s  𝑣 ) )  | 
						
						
							| 146 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑥  ·s  𝑤 ) )  | 
						
						
							| 147 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( 𝑦𝑂  ·s  𝑥 )  =  ( 𝑤  ·s  𝑥 ) )  | 
						
						
							| 148 | 
							
								146 147
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 )  ↔  ( 𝑥  ·s  𝑤 )  =  ( 𝑤  ·s  𝑥 ) ) )  | 
						
						
							| 149 | 
							
								
							 | 
							simplr3 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) )  | 
						
						
							| 150 | 
							
								
							 | 
							simprr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑤  ∈  (  L  ‘ 𝑦 ) )  | 
						
						
							| 151 | 
							
								
							 | 
							elun1 | 
							⊢ ( 𝑤  ∈  (  L  ‘ 𝑦 )  →  𝑤  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 152 | 
							
								150 151
							 | 
							syl | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑤  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) )  | 
						
						
							| 153 | 
							
								148 149 152
							 | 
							rspcdva | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑥  ·s  𝑤 )  =  ( 𝑤  ·s  𝑥 ) )  | 
						
						
							| 154 | 
							
								145 153
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  =  ( ( 𝑦  ·s  𝑣 )  +s  ( 𝑤  ·s  𝑥 ) ) )  | 
						
						
							| 155 | 
							
								
							 | 
							simpllr | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑦  ∈   No  )  | 
						
						
							| 156 | 
							
								75 142
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑣  ∈   No  )  | 
						
						
							| 157 | 
							
								155 156
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑦  ·s  𝑣 )  ∈   No  )  | 
						
						
							| 158 | 
							
								37 150
							 | 
							sselid | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑤  ∈   No  )  | 
						
						
							| 159 | 
							
								
							 | 
							simplll | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  𝑥  ∈   No  )  | 
						
						
							| 160 | 
							
								158 159
							 | 
							mulscld | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑤  ·s  𝑥 )  ∈   No  )  | 
						
						
							| 161 | 
							
								157 160
							 | 
							addscomd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑦  ·s  𝑣 )  +s  ( 𝑤  ·s  𝑥 ) )  =  ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) ) )  | 
						
						
							| 162 | 
							
								154 161
							 | 
							eqtrd | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  =  ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) ) )  | 
						
						
							| 163 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑣  ·s  𝑦𝑂 ) )  | 
						
						
							| 164 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( 𝑦𝑂  ·s  𝑥𝑂 )  =  ( 𝑦𝑂  ·s  𝑣 ) )  | 
						
						
							| 165 | 
							
								163 164
							 | 
							eqeq12d | 
							⊢ ( 𝑥𝑂  =  𝑣  →  ( ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ↔  ( 𝑣  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑣 ) ) )  | 
						
						
							| 166 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( 𝑣  ·s  𝑦𝑂 )  =  ( 𝑣  ·s  𝑤 ) )  | 
						
						
							| 167 | 
							
								
							 | 
							oveq1 | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( 𝑦𝑂  ·s  𝑣 )  =  ( 𝑤  ·s  𝑣 ) )  | 
						
						
							| 168 | 
							
								166 167
							 | 
							eqeq12d | 
							⊢ ( 𝑦𝑂  =  𝑤  →  ( ( 𝑣  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑣 )  ↔  ( 𝑣  ·s  𝑤 )  =  ( 𝑤  ·s  𝑣 ) ) )  | 
						
						
							| 169 | 
							
								
							 | 
							simplr1 | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 ) )  | 
						
						
							| 170 | 
							
								165 168 169 144 152
							 | 
							rspc2dv | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑣  ·s  𝑤 )  =  ( 𝑤  ·s  𝑣 ) )  | 
						
						
							| 171 | 
							
								162 170
							 | 
							oveq12d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) )  | 
						
						
							| 172 | 
							
								171
							 | 
							eqeq2d | 
							⊢ ( ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  ∧  ( 𝑣  ∈  (  R  ‘ 𝑥 )  ∧  𝑤  ∈  (  L  ‘ 𝑦 ) ) )  →  ( 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  ↔  𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) ) )  | 
						
						
							| 173 | 
							
								172
							 | 
							2rexbidva | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  ↔  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) ) )  | 
						
						
							| 174 | 
							
								
							 | 
							rexcom | 
							⊢ ( ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) )  ↔  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) )  | 
						
						
							| 175 | 
							
								173 174
							 | 
							bitrdi | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  ↔  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) ) )  | 
						
						
							| 176 | 
							
								175
							 | 
							abbidv | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) }  =  { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) } )  | 
						
						
							| 177 | 
							
								137 176
							 | 
							uneq12d | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } )  =  ( { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) } ) )  | 
						
						
							| 178 | 
							
								
							 | 
							uncom | 
							⊢ ( { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) } )  =  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } )  | 
						
						
							| 179 | 
							
								177 178
							 | 
							eqtrdi | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } )  =  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } ) )  | 
						
						
							| 180 | 
							
								98 179
							 | 
							oveq12d | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) )  =  ( ( { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } )  |s  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } ) ) )  | 
						
						
							| 181 | 
							
								
							 | 
							mulsval | 
							⊢ ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  →  ( 𝑥  ·s  𝑦 )  =  ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) ) )  | 
						
						
							| 182 | 
							
								181
							 | 
							adantr | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( 𝑥  ·s  𝑦 )  =  ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) 𝑎  =  ( ( ( 𝑝  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) 𝑏  =  ( ( ( 𝑟  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) 𝑐  =  ( ( ( 𝑡  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) 𝑑  =  ( ( ( 𝑣  ·s  𝑦 )  +s  ( 𝑥  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) ) )  | 
						
						
							| 183 | 
							
								
							 | 
							mulsval | 
							⊢ ( ( 𝑦  ∈   No   ∧  𝑥  ∈   No  )  →  ( 𝑦  ·s  𝑥 )  =  ( ( { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } )  |s  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } ) ) )  | 
						
						
							| 184 | 
							
								183
							 | 
							ancoms | 
							⊢ ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  →  ( 𝑦  ·s  𝑥 )  =  ( ( { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } )  |s  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } ) ) )  | 
						
						
							| 185 | 
							
								184
							 | 
							adantr | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( 𝑦  ·s  𝑥 )  =  ( ( { 𝑎  ∣  ∃ 𝑞  ∈  (  L  ‘ 𝑦 ) ∃ 𝑝  ∈  (  L  ‘ 𝑥 ) 𝑎  =  ( ( ( 𝑞  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑝 ) )  -s  ( 𝑞  ·s  𝑝 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑠  ∈  (  R  ‘ 𝑦 ) ∃ 𝑟  ∈  (  R  ‘ 𝑥 ) 𝑏  =  ( ( ( 𝑠  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑟 ) )  -s  ( 𝑠  ·s  𝑟 ) ) } )  |s  ( { 𝑑  ∣  ∃ 𝑤  ∈  (  L  ‘ 𝑦 ) ∃ 𝑣  ∈  (  R  ‘ 𝑥 ) 𝑑  =  ( ( ( 𝑤  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑣 ) )  -s  ( 𝑤  ·s  𝑣 ) ) }  ∪  { 𝑐  ∣  ∃ 𝑢  ∈  (  R  ‘ 𝑦 ) ∃ 𝑡  ∈  (  L  ‘ 𝑥 ) 𝑐  =  ( ( ( 𝑢  ·s  𝑥 )  +s  ( 𝑦  ·s  𝑡 ) )  -s  ( 𝑢  ·s  𝑡 ) ) } ) ) )  | 
						
						
							| 186 | 
							
								180 182 185
							 | 
							3eqtr4d | 
							⊢ ( ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  ∧  ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) ) )  →  ( 𝑥  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥 ) )  | 
						
						
							| 187 | 
							
								186
							 | 
							ex | 
							⊢ ( ( 𝑥  ∈   No   ∧  𝑦  ∈   No  )  →  ( ( ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥𝑂  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥𝑂 )  ∧  ∀ 𝑥𝑂  ∈  ( (  L  ‘ 𝑥 )  ∪  (  R  ‘ 𝑥 ) ) ( 𝑥𝑂  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥𝑂 )  ∧  ∀ 𝑦𝑂  ∈  ( (  L  ‘ 𝑦 )  ∪  (  R  ‘ 𝑦 ) ) ( 𝑥  ·s  𝑦𝑂 )  =  ( 𝑦𝑂  ·s  𝑥 ) )  →  ( 𝑥  ·s  𝑦 )  =  ( 𝑦  ·s  𝑥 ) ) )  | 
						
						
							| 188 | 
							
								3 6 9 12 15 187
							 | 
							no2inds | 
							⊢ ( ( 𝐴  ∈   No   ∧  𝐵  ∈   No  )  →  ( 𝐴  ·s  𝐵 )  =  ( 𝐵  ·s  𝐴 ) )  |