| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2arympt.f | ⊢ 𝐹  =  ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  ↦  ( ( 𝑥 ‘ 0 ) 𝑂 ( 𝑥 ‘ 1 ) ) ) | 
						
							| 2 |  | simplr | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  ∧  𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } ) )  →  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 ) | 
						
							| 3 |  | elmapi | ⊢ ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  →  𝑥 : { 0 ,  1 } ⟶ 𝑋 ) | 
						
							| 4 |  | c0ex | ⊢ 0  ∈  V | 
						
							| 5 | 4 | prid1 | ⊢ 0  ∈  { 0 ,  1 } | 
						
							| 6 | 5 | a1i | ⊢ ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  →  0  ∈  { 0 ,  1 } ) | 
						
							| 7 | 3 6 | ffvelcdmd | ⊢ ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  →  ( 𝑥 ‘ 0 )  ∈  𝑋 ) | 
						
							| 8 | 7 | adantl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  ∧  𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } ) )  →  ( 𝑥 ‘ 0 )  ∈  𝑋 ) | 
						
							| 9 |  | 1ex | ⊢ 1  ∈  V | 
						
							| 10 | 9 | prid2 | ⊢ 1  ∈  { 0 ,  1 } | 
						
							| 11 | 10 | a1i | ⊢ ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  →  1  ∈  { 0 ,  1 } ) | 
						
							| 12 | 3 11 | ffvelcdmd | ⊢ ( 𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } )  →  ( 𝑥 ‘ 1 )  ∈  𝑋 ) | 
						
							| 13 | 12 | adantl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  ∧  𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } ) )  →  ( 𝑥 ‘ 1 )  ∈  𝑋 ) | 
						
							| 14 | 2 8 13 | fovcdmd | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  ∧  𝑥  ∈  ( 𝑋  ↑m  { 0 ,  1 } ) )  →  ( ( 𝑥 ‘ 0 ) 𝑂 ( 𝑥 ‘ 1 ) )  ∈  𝑋 ) | 
						
							| 15 | 14 1 | fmptd | ⊢ ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  →  𝐹 : ( 𝑋  ↑m  { 0 ,  1 } ) ⟶ 𝑋 ) | 
						
							| 16 |  | 2aryfvalel | ⊢ ( 𝑋  ∈  𝑉  →  ( 𝐹  ∈  ( 2 -aryF  𝑋 )  ↔  𝐹 : ( 𝑋  ↑m  { 0 ,  1 } ) ⟶ 𝑋 ) ) | 
						
							| 17 | 16 | adantr | ⊢ ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  →  ( 𝐹  ∈  ( 2 -aryF  𝑋 )  ↔  𝐹 : ( 𝑋  ↑m  { 0 ,  1 } ) ⟶ 𝑋 ) ) | 
						
							| 18 | 15 17 | mpbird | ⊢ ( ( 𝑋  ∈  𝑉  ∧  𝑂 : ( 𝑋  ×  𝑋 ) ⟶ 𝑋 )  →  𝐹  ∈  ( 2 -aryF  𝑋 ) ) |