| Step | Hyp | Ref | Expression | 
						
							| 1 |  | f1ocpbl.f | ⊢ ( 𝜑  →  𝐹 : 𝑉 –1-1-onto→ 𝑋 ) | 
						
							| 2 |  | f1of1 | ⊢ ( 𝐹 : 𝑉 –1-1-onto→ 𝑋  →  𝐹 : 𝑉 –1-1→ 𝑋 ) | 
						
							| 3 | 1 2 | syl | ⊢ ( 𝜑  →  𝐹 : 𝑉 –1-1→ 𝑋 ) | 
						
							| 4 | 3 | 3ad2ant1 | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  𝐹 : 𝑉 –1-1→ 𝑋 ) | 
						
							| 5 |  | simp2l | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  𝐴  ∈  𝑉 ) | 
						
							| 6 |  | simp3l | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  𝐶  ∈  𝑉 ) | 
						
							| 7 |  | f1fveq | ⊢ ( ( 𝐹 : 𝑉 –1-1→ 𝑋  ∧  ( 𝐴  ∈  𝑉  ∧  𝐶  ∈  𝑉 ) )  →  ( ( 𝐹 ‘ 𝐴 )  =  ( 𝐹 ‘ 𝐶 )  ↔  𝐴  =  𝐶 ) ) | 
						
							| 8 | 4 5 6 7 | syl12anc | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( ( 𝐹 ‘ 𝐴 )  =  ( 𝐹 ‘ 𝐶 )  ↔  𝐴  =  𝐶 ) ) | 
						
							| 9 |  | simp2r | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  𝐵  ∈  𝑉 ) | 
						
							| 10 |  | simp3r | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  𝐷  ∈  𝑉 ) | 
						
							| 11 |  | f1fveq | ⊢ ( ( 𝐹 : 𝑉 –1-1→ 𝑋  ∧  ( 𝐵  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( ( 𝐹 ‘ 𝐵 )  =  ( 𝐹 ‘ 𝐷 )  ↔  𝐵  =  𝐷 ) ) | 
						
							| 12 | 4 9 10 11 | syl12anc | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( ( 𝐹 ‘ 𝐵 )  =  ( 𝐹 ‘ 𝐷 )  ↔  𝐵  =  𝐷 ) ) | 
						
							| 13 | 8 12 | anbi12d | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉 )  ∧  ( 𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( ( ( 𝐹 ‘ 𝐴 )  =  ( 𝐹 ‘ 𝐶 )  ∧  ( 𝐹 ‘ 𝐵 )  =  ( 𝐹 ‘ 𝐷 ) )  ↔  ( 𝐴  =  𝐶  ∧  𝐵  =  𝐷 ) ) ) |