| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dmplp | 
							⊢ dom   +P   =  ( P  ×  P )  | 
						
						
							| 2 | 
							
								
							 | 
							ltrelpr | 
							⊢ <P   ⊆  ( P  ×  P )  | 
						
						
							| 3 | 
							
								
							 | 
							0npr | 
							⊢ ¬  ∅  ∈  P  | 
						
						
							| 4 | 
							
								
							 | 
							ltaprlem | 
							⊢ ( 𝐶  ∈  P  →  ( 𝐴 <P  𝐵  →  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 5 | 
							
								4
							 | 
							adantr | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( 𝐴 <P  𝐵  →  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 6 | 
							
								
							 | 
							olc | 
							⊢ ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  ( ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 )  ∨  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 7 | 
							
								
							 | 
							ltaprlem | 
							⊢ ( 𝐶  ∈  P  →  ( 𝐵 <P  𝐴  →  ( 𝐶  +P  𝐵 ) <P  ( 𝐶  +P  𝐴 ) ) )  | 
						
						
							| 8 | 
							
								7
							 | 
							adantr | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( 𝐵 <P  𝐴  →  ( 𝐶  +P  𝐵 ) <P  ( 𝐶  +P  𝐴 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							ltsopr | 
							⊢ <P   Or  P  | 
						
						
							| 10 | 
							
								
							 | 
							sotric | 
							⊢ ( ( <P   Or  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( 𝐵 <P  𝐴  ↔  ¬  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 11 | 
							
								9 10
							 | 
							mpan | 
							⊢ ( ( 𝐵  ∈  P  ∧  𝐴  ∈  P )  →  ( 𝐵 <P  𝐴  ↔  ¬  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							adantl | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( 𝐵 <P  𝐴  ↔  ¬  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 13 | 
							
								
							 | 
							addclpr | 
							⊢ ( ( 𝐶  ∈  P  ∧  𝐵  ∈  P )  →  ( 𝐶  +P  𝐵 )  ∈  P )  | 
						
						
							| 14 | 
							
								
							 | 
							addclpr | 
							⊢ ( ( 𝐶  ∈  P  ∧  𝐴  ∈  P )  →  ( 𝐶  +P  𝐴 )  ∈  P )  | 
						
						
							| 15 | 
							
								13 14
							 | 
							anim12dan | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( 𝐶  +P  𝐵 )  ∈  P  ∧  ( 𝐶  +P  𝐴 )  ∈  P ) )  | 
						
						
							| 16 | 
							
								
							 | 
							sotric | 
							⊢ ( ( <P   Or  P  ∧  ( ( 𝐶  +P  𝐵 )  ∈  P  ∧  ( 𝐶  +P  𝐴 )  ∈  P ) )  →  ( ( 𝐶  +P  𝐵 ) <P  ( 𝐶  +P  𝐴 )  ↔  ¬  ( ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 )  ∨  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) ) )  | 
						
						
							| 17 | 
							
								9 15 16
							 | 
							sylancr | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( 𝐶  +P  𝐵 ) <P  ( 𝐶  +P  𝐴 )  ↔  ¬  ( ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 )  ∨  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) ) )  | 
						
						
							| 18 | 
							
								8 12 17
							 | 
							3imtr3d | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ¬  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 )  →  ¬  ( ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 )  ∨  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) ) )  | 
						
						
							| 19 | 
							
								18
							 | 
							con4d | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 )  ∨  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) )  →  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 20 | 
							
								6 19
							 | 
							syl5 | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 21 | 
							
								
							 | 
							df-or | 
							⊢ ( ( 𝐵  =  𝐴  ∨  𝐴 <P  𝐵 )  ↔  ( ¬  𝐵  =  𝐴  →  𝐴 <P  𝐵 ) )  | 
						
						
							| 22 | 
							
								20 21
							 | 
							imbitrdi | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  ( ¬  𝐵  =  𝐴  →  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 23 | 
							
								22
							 | 
							com23 | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ¬  𝐵  =  𝐴  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  𝐴 <P  𝐵 ) ) )  | 
						
						
							| 24 | 
							
								9 2
							 | 
							soirri | 
							⊢ ¬  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐴 )  | 
						
						
							| 25 | 
							
								
							 | 
							oveq2 | 
							⊢ ( 𝐵  =  𝐴  →  ( 𝐶  +P  𝐵 )  =  ( 𝐶  +P  𝐴 ) )  | 
						
						
							| 26 | 
							
								25
							 | 
							breq2d | 
							⊢ ( 𝐵  =  𝐴  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  ↔  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐴 ) ) )  | 
						
						
							| 27 | 
							
								24 26
							 | 
							mtbiri | 
							⊢ ( 𝐵  =  𝐴  →  ¬  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) )  | 
						
						
							| 28 | 
							
								27
							 | 
							pm2.21d | 
							⊢ ( 𝐵  =  𝐴  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  𝐴 <P  𝐵 ) )  | 
						
						
							| 29 | 
							
								23 28
							 | 
							pm2.61d2 | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 )  →  𝐴 <P  𝐵 ) )  | 
						
						
							| 30 | 
							
								5 29
							 | 
							impbid | 
							⊢ ( ( 𝐶  ∈  P  ∧  ( 𝐵  ∈  P  ∧  𝐴  ∈  P ) )  →  ( 𝐴 <P  𝐵  ↔  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 31 | 
							
								30
							 | 
							3impb | 
							⊢ ( ( 𝐶  ∈  P  ∧  𝐵  ∈  P  ∧  𝐴  ∈  P )  →  ( 𝐴 <P  𝐵  ↔  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 32 | 
							
								31
							 | 
							3com13 | 
							⊢ ( ( 𝐴  ∈  P  ∧  𝐵  ∈  P  ∧  𝐶  ∈  P )  →  ( 𝐴 <P  𝐵  ↔  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  | 
						
						
							| 33 | 
							
								1 2 3 32
							 | 
							ndmovord | 
							⊢ ( 𝐶  ∈  P  →  ( 𝐴 <P  𝐵  ↔  ( 𝐶  +P  𝐴 ) <P  ( 𝐶  +P  𝐵 ) ) )  |