| Step | Hyp | Ref | Expression | 
						
							| 1 |  | coiun | ⊢ ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ∪  𝑥  ∈  𝐴 ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) )  =  ∪  𝑥  ∈  𝐴 ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) | 
						
							| 2 |  | inss1 | ⊢ ( dom  𝐹  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  dom  𝐹 | 
						
							| 3 |  | fndm | ⊢ ( 𝐹  Fn  𝐴  →  dom  𝐹  =  𝐴 ) | 
						
							| 4 | 2 3 | sseqtrid | ⊢ ( 𝐹  Fn  𝐴  →  ( dom  𝐹  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  𝐴 ) | 
						
							| 5 |  | dfco2a | ⊢ ( ( dom  𝐹  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  𝐴  →  ( 𝐹  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ∪  𝑥  ∈  𝐴 ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) | 
						
							| 6 | 4 5 | syl | ⊢ ( 𝐹  Fn  𝐴  →  ( 𝐹  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ∪  𝑥  ∈  𝐴 ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) | 
						
							| 7 | 6 | coeq2d | ⊢ ( 𝐹  Fn  𝐴  →  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( 𝐹  ∘  ( 1st   ↾  ( V  ×  V ) ) ) )  =  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ∪  𝑥  ∈  𝐴 ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) ) | 
						
							| 8 |  | inss1 | ⊢ ( dom  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  dom  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 9 |  | dmxpss | ⊢ dom  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ⊆  { ( 𝐹 ‘ 𝑥 ) } | 
						
							| 10 | 8 9 | sstri | ⊢ ( dom  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  { ( 𝐹 ‘ 𝑥 ) } | 
						
							| 11 |  | dfco2a | ⊢ ( ( dom  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∩  ran  ( 1st   ↾  ( V  ×  V ) ) )  ⊆  { ( 𝐹 ‘ 𝑥 ) }  →  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ∪  𝑦  ∈  { ( 𝐹 ‘ 𝑥 ) } ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  ×  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } ) ) ) | 
						
							| 12 | 10 11 | ax-mp | ⊢ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ∪  𝑦  ∈  { ( 𝐹 ‘ 𝑥 ) } ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  ×  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } ) ) | 
						
							| 13 |  | fvex | ⊢ ( 𝐹 ‘ 𝑥 )  ∈  V | 
						
							| 14 |  | fparlem1 | ⊢ ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  =  ( { 𝑦 }  ×  V ) | 
						
							| 15 |  | sneq | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  { 𝑦 }  =  { ( 𝐹 ‘ 𝑥 ) } ) | 
						
							| 16 | 15 | xpeq1d | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ( { 𝑦 }  ×  V )  =  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) ) | 
						
							| 17 | 14 16 | eqtrid | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  =  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) ) | 
						
							| 18 | 15 | imaeq2d | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } )  =  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { ( 𝐹 ‘ 𝑥 ) } ) ) | 
						
							| 19 |  | df-ima | ⊢ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { ( 𝐹 ‘ 𝑥 ) } )  =  ran  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ↾  { ( 𝐹 ‘ 𝑥 ) } ) | 
						
							| 20 |  | ssid | ⊢ { ( 𝐹 ‘ 𝑥 ) }  ⊆  { ( 𝐹 ‘ 𝑥 ) } | 
						
							| 21 |  | xpssres | ⊢ ( { ( 𝐹 ‘ 𝑥 ) }  ⊆  { ( 𝐹 ‘ 𝑥 ) }  →  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ↾  { ( 𝐹 ‘ 𝑥 ) } )  =  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) ) | 
						
							| 22 | 20 21 | ax-mp | ⊢ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ↾  { ( 𝐹 ‘ 𝑥 ) } )  =  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 23 | 22 | rneqi | ⊢ ran  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ↾  { ( 𝐹 ‘ 𝑥 ) } )  =  ran  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 24 | 13 | snnz | ⊢ { ( 𝐹 ‘ 𝑥 ) }  ≠  ∅ | 
						
							| 25 |  | rnxp | ⊢ ( { ( 𝐹 ‘ 𝑥 ) }  ≠  ∅  →  ran  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  =  ( { 𝑥 }  ×  V ) ) | 
						
							| 26 | 24 25 | ax-mp | ⊢ ran  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  =  ( { 𝑥 }  ×  V ) | 
						
							| 27 | 23 26 | eqtri | ⊢ ran  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ↾  { ( 𝐹 ‘ 𝑥 ) } )  =  ( { 𝑥 }  ×  V ) | 
						
							| 28 | 19 27 | eqtri | ⊢ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { ( 𝐹 ‘ 𝑥 ) } )  =  ( { 𝑥 }  ×  V ) | 
						
							| 29 | 18 28 | eqtrdi | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } )  =  ( { 𝑥 }  ×  V ) ) | 
						
							| 30 | 17 29 | xpeq12d | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  ×  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } ) )  =  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  V )  ×  ( { 𝑥 }  ×  V ) ) ) | 
						
							| 31 | 13 30 | iunxsn | ⊢ ∪  𝑦  ∈  { ( 𝐹 ‘ 𝑥 ) } ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑦 } )  ×  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  “  { 𝑦 } ) )  =  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  V )  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 32 | 12 31 | eqtri | ⊢ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  V )  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 33 | 32 | cnveqi | ⊢ ◡ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ◡ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  V )  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 34 |  | cnvco | ⊢ ◡ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  ∘  ( 1st   ↾  ( V  ×  V ) ) )  =  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ◡ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) ) | 
						
							| 35 |  | cnvxp | ⊢ ◡ ( ( { ( 𝐹 ‘ 𝑥 ) }  ×  V )  ×  ( { 𝑥 }  ×  V ) )  =  ( ( { 𝑥 }  ×  V )  ×  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) ) | 
						
							| 36 | 33 34 35 | 3eqtr3i | ⊢ ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ◡ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) )  =  ( ( { 𝑥 }  ×  V )  ×  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) ) | 
						
							| 37 |  | fparlem1 | ⊢ ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  =  ( { 𝑥 }  ×  V ) | 
						
							| 38 | 37 | xpeq2i | ⊢ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) )  =  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) | 
						
							| 39 |  | fnsnfv | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  { ( 𝐹 ‘ 𝑥 ) }  =  ( 𝐹  “  { 𝑥 } ) ) | 
						
							| 40 | 39 | xpeq1d | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) )  =  ( ( 𝐹  “  { 𝑥 } )  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) ) ) | 
						
							| 41 | 38 40 | eqtr3id | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  =  ( ( 𝐹  “  { 𝑥 } )  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) ) ) | 
						
							| 42 | 41 | cnveqd | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ◡ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  =  ◡ ( ( 𝐹  “  { 𝑥 } )  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) ) ) | 
						
							| 43 |  | cnvxp | ⊢ ◡ ( ( 𝐹  “  { 𝑥 } )  ×  ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } ) )  =  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) | 
						
							| 44 | 42 43 | eqtrdi | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ◡ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) )  =  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) | 
						
							| 45 | 44 | coeq2d | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ◡ ( { ( 𝐹 ‘ 𝑥 ) }  ×  ( { 𝑥 }  ×  V ) ) )  =  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) ) | 
						
							| 46 | 36 45 | eqtr3id | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( { 𝑥 }  ×  V )  ×  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) )  =  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) ) | 
						
							| 47 | 46 | iuneq2dv | ⊢ ( 𝐹  Fn  𝐴  →  ∪  𝑥  ∈  𝐴 ( ( { 𝑥 }  ×  V )  ×  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) )  =  ∪  𝑥  ∈  𝐴 ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  “  { 𝑥 } )  ×  ( 𝐹  “  { 𝑥 } ) ) ) ) | 
						
							| 48 | 1 7 47 | 3eqtr4a | ⊢ ( 𝐹  Fn  𝐴  →  ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( 𝐹  ∘  ( 1st   ↾  ( V  ×  V ) ) ) )  =  ∪  𝑥  ∈  𝐴 ( ( { 𝑥 }  ×  V )  ×  ( { ( 𝐹 ‘ 𝑥 ) }  ×  V ) ) ) |