| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ptbas.1 | ⊢ 𝐵  =  { 𝑥  ∣  ∃ 𝑔 ( ( 𝑔  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝑔 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑧  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑧 ) ( 𝑔 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ∧  𝑥  =  X 𝑦  ∈  𝐴 ( 𝑔 ‘ 𝑦 ) ) } | 
						
							| 2 |  | simp2l | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  𝐺  Fn  𝐴 ) | 
						
							| 3 |  | simp1 | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  𝐴  ∈  𝑉 ) | 
						
							| 4 | 2 3 | fnexd | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  𝐺  ∈  V ) | 
						
							| 5 |  | simp2r | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 6 |  | difeq2 | ⊢ ( 𝑤  =  𝑊  →  ( 𝐴  ∖  𝑤 )  =  ( 𝐴  ∖  𝑊 ) ) | 
						
							| 7 | 6 | raleqdv | ⊢ ( 𝑤  =  𝑊  →  ( ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 )  ↔  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 8 | 7 | rspcev | ⊢ ( ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  →  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 9 | 8 | 3ad2ant3 | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 10 | 2 5 9 | 3jca | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 11 |  | fveq1 | ⊢ ( ℎ  =  𝐺  →  ( ℎ ‘ 𝑦 )  =  ( 𝐺 ‘ 𝑦 ) ) | 
						
							| 12 | 11 | eqcomd | ⊢ ( ℎ  =  𝐺  →  ( 𝐺 ‘ 𝑦 )  =  ( ℎ ‘ 𝑦 ) ) | 
						
							| 13 | 12 | ixpeq2dv | ⊢ ( ℎ  =  𝐺  →  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  =  X 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 ) ) | 
						
							| 14 | 13 | biantrud | ⊢ ( ℎ  =  𝐺  →  ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ↔  ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ∧  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  =  X 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 ) ) ) ) | 
						
							| 15 |  | fneq1 | ⊢ ( ℎ  =  𝐺  →  ( ℎ  Fn  𝐴  ↔  𝐺  Fn  𝐴 ) ) | 
						
							| 16 | 11 | eleq1d | ⊢ ( ℎ  =  𝐺  →  ( ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ↔  ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 17 | 16 | ralbidv | ⊢ ( ℎ  =  𝐺  →  ( ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ↔  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 18 | 11 | eqeq1d | ⊢ ( ℎ  =  𝐺  →  ( ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 )  ↔  ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 19 | 18 | rexralbidv | ⊢ ( ℎ  =  𝐺  →  ( ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 )  ↔  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 20 | 15 17 19 | 3anbi123d | ⊢ ( ℎ  =  𝐺  →  ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ↔  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) ) | 
						
							| 21 | 14 20 | bitr3d | ⊢ ( ℎ  =  𝐺  →  ( ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ∧  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  =  X 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 ) )  ↔  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) ) ) | 
						
							| 22 | 4 10 21 | spcedv | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  ∃ ℎ ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ∧  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  =  X 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 ) ) ) | 
						
							| 23 | 1 | elpt | ⊢ ( X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  𝐵  ↔  ∃ ℎ ( ( ℎ  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 )  ∧  ∃ 𝑤  ∈  Fin ∀ 𝑦  ∈  ( 𝐴  ∖  𝑤 ) ( ℎ ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) )  ∧  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  =  X 𝑦  ∈  𝐴 ( ℎ ‘ 𝑦 ) ) ) | 
						
							| 24 | 22 23 | sylibr | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( 𝐺  Fn  𝐴  ∧  ∀ 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  ( 𝐹 ‘ 𝑦 ) )  ∧  ( 𝑊  ∈  Fin  ∧  ∀ 𝑦  ∈  ( 𝐴  ∖  𝑊 ) ( 𝐺 ‘ 𝑦 )  =  ∪  ( 𝐹 ‘ 𝑦 ) ) )  →  X 𝑦  ∈  𝐴 ( 𝐺 ‘ 𝑦 )  ∈  𝐵 ) |