| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ffnafv | ⊢ ( 𝐹 : ( 𝐴  ×  𝐵 ) ⟶ 𝐶  ↔  ( 𝐹  Fn  ( 𝐴  ×  𝐵 )  ∧  ∀ 𝑤  ∈  ( 𝐴  ×  𝐵 ) ( 𝐹 ''' 𝑤 )  ∈  𝐶 ) ) | 
						
							| 2 |  | afveq2 | ⊢ ( 𝑤  =  〈 𝑥 ,  𝑦 〉  →  ( 𝐹 ''' 𝑤 )  =  ( 𝐹 ''' 〈 𝑥 ,  𝑦 〉 ) ) | 
						
							| 3 |  | df-aov | ⊢  (( 𝑥 𝐹 𝑦 ))   =  ( 𝐹 ''' 〈 𝑥 ,  𝑦 〉 ) | 
						
							| 4 | 2 3 | eqtr4di | ⊢ ( 𝑤  =  〈 𝑥 ,  𝑦 〉  →  ( 𝐹 ''' 𝑤 )  =   (( 𝑥 𝐹 𝑦 ))  ) | 
						
							| 5 | 4 | eleq1d | ⊢ ( 𝑤  =  〈 𝑥 ,  𝑦 〉  →  ( ( 𝐹 ''' 𝑤 )  ∈  𝐶  ↔   (( 𝑥 𝐹 𝑦 ))   ∈  𝐶 ) ) | 
						
							| 6 | 5 | ralxp | ⊢ ( ∀ 𝑤  ∈  ( 𝐴  ×  𝐵 ) ( 𝐹 ''' 𝑤 )  ∈  𝐶  ↔  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵  (( 𝑥 𝐹 𝑦 ))   ∈  𝐶 ) | 
						
							| 7 | 6 | anbi2i | ⊢ ( ( 𝐹  Fn  ( 𝐴  ×  𝐵 )  ∧  ∀ 𝑤  ∈  ( 𝐴  ×  𝐵 ) ( 𝐹 ''' 𝑤 )  ∈  𝐶 )  ↔  ( 𝐹  Fn  ( 𝐴  ×  𝐵 )  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵  (( 𝑥 𝐹 𝑦 ))   ∈  𝐶 ) ) | 
						
							| 8 | 1 7 | bitri | ⊢ ( 𝐹 : ( 𝐴  ×  𝐵 ) ⟶ 𝐶  ↔  ( 𝐹  Fn  ( 𝐴  ×  𝐵 )  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐵  (( 𝑥 𝐹 𝑦 ))   ∈  𝐶 ) ) |