| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simprl | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  𝑤  ∈   No  ) | 
						
							| 2 |  | simpl3 | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  𝐵  ∈   No  ) | 
						
							| 3 | 1 2 | mulscld | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  ( 𝑤  ·s  𝐵 )  ∈   No  ) | 
						
							| 4 |  | oveq1 | ⊢ ( ( 𝐴  ·s  𝑤 )  =   1s   →  ( ( 𝐴  ·s  𝑤 )  ·s  𝐵 )  =  (  1s   ·s  𝐵 ) ) | 
						
							| 5 | 4 | adantl | ⊢ ( ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  )  →  ( ( 𝐴  ·s  𝑤 )  ·s  𝐵 )  =  (  1s   ·s  𝐵 ) ) | 
						
							| 6 | 5 | adantl | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  ( ( 𝐴  ·s  𝑤 )  ·s  𝐵 )  =  (  1s   ·s  𝐵 ) ) | 
						
							| 7 |  | simpl1 | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  𝐴  ∈   No  ) | 
						
							| 8 | 7 1 2 | mulsassd | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  ( ( 𝐴  ·s  𝑤 )  ·s  𝐵 )  =  ( 𝐴  ·s  ( 𝑤  ·s  𝐵 ) ) ) | 
						
							| 9 | 2 | mulslidd | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  (  1s   ·s  𝐵 )  =  𝐵 ) | 
						
							| 10 | 6 8 9 | 3eqtr3d | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  ( 𝐴  ·s  ( 𝑤  ·s  𝐵 ) )  =  𝐵 ) | 
						
							| 11 |  | oveq2 | ⊢ ( 𝑧  =  ( 𝑤  ·s  𝐵 )  →  ( 𝐴  ·s  𝑧 )  =  ( 𝐴  ·s  ( 𝑤  ·s  𝐵 ) ) ) | 
						
							| 12 | 11 | eqeq1d | ⊢ ( 𝑧  =  ( 𝑤  ·s  𝐵 )  →  ( ( 𝐴  ·s  𝑧 )  =  𝐵  ↔  ( 𝐴  ·s  ( 𝑤  ·s  𝐵 ) )  =  𝐵 ) ) | 
						
							| 13 | 12 | rspcev | ⊢ ( ( ( 𝑤  ·s  𝐵 )  ∈   No   ∧  ( 𝐴  ·s  ( 𝑤  ·s  𝐵 ) )  =  𝐵 )  →  ∃ 𝑧  ∈   No  ( 𝐴  ·s  𝑧 )  =  𝐵 ) | 
						
							| 14 | 3 10 13 | syl2anc | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ( 𝑤  ∈   No   ∧  ( 𝐴  ·s  𝑤 )  =   1s  ) )  →  ∃ 𝑧  ∈   No  ( 𝐴  ·s  𝑧 )  =  𝐵 ) | 
						
							| 15 | 14 | rexlimdvaa | ⊢ ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  →  ( ∃ 𝑤  ∈   No  ( 𝐴  ·s  𝑤 )  =   1s   →  ∃ 𝑧  ∈   No  ( 𝐴  ·s  𝑧 )  =  𝐵 ) ) | 
						
							| 16 | 15 | imp | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ∃ 𝑤  ∈   No  ( 𝐴  ·s  𝑤 )  =   1s  )  →  ∃ 𝑧  ∈   No  ( 𝐴  ·s  𝑧 )  =  𝐵 ) | 
						
							| 17 |  | oveq2 | ⊢ ( 𝑥  =  𝑤  →  ( 𝐴  ·s  𝑥 )  =  ( 𝐴  ·s  𝑤 ) ) | 
						
							| 18 | 17 | eqeq1d | ⊢ ( 𝑥  =  𝑤  →  ( ( 𝐴  ·s  𝑥 )  =   1s   ↔  ( 𝐴  ·s  𝑤 )  =   1s  ) ) | 
						
							| 19 | 18 | cbvrexvw | ⊢ ( ∃ 𝑥  ∈   No  ( 𝐴  ·s  𝑥 )  =   1s   ↔  ∃ 𝑤  ∈   No  ( 𝐴  ·s  𝑤 )  =   1s  ) | 
						
							| 20 | 19 | anbi2i | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ∃ 𝑥  ∈   No  ( 𝐴  ·s  𝑥 )  =   1s  )  ↔  ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ∃ 𝑤  ∈   No  ( 𝐴  ·s  𝑤 )  =   1s  ) ) | 
						
							| 21 |  | oveq2 | ⊢ ( 𝑦  =  𝑧  →  ( 𝐴  ·s  𝑦 )  =  ( 𝐴  ·s  𝑧 ) ) | 
						
							| 22 | 21 | eqeq1d | ⊢ ( 𝑦  =  𝑧  →  ( ( 𝐴  ·s  𝑦 )  =  𝐵  ↔  ( 𝐴  ·s  𝑧 )  =  𝐵 ) ) | 
						
							| 23 | 22 | cbvrexvw | ⊢ ( ∃ 𝑦  ∈   No  ( 𝐴  ·s  𝑦 )  =  𝐵  ↔  ∃ 𝑧  ∈   No  ( 𝐴  ·s  𝑧 )  =  𝐵 ) | 
						
							| 24 | 16 20 23 | 3imtr4i | ⊢ ( ( ( 𝐴  ∈   No   ∧  𝐴  ≠   0s   ∧  𝐵  ∈   No  )  ∧  ∃ 𝑥  ∈   No  ( 𝐴  ·s  𝑥 )  =   1s  )  →  ∃ 𝑦  ∈   No  ( 𝐴  ·s  𝑦 )  =  𝐵 ) |