| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							elpwi | 
							⊢ ( 𝑎  ∈  𝒫  𝑋  →  𝑎  ⊆  𝑋 )  | 
						
						
							| 2 | 
							
								
							 | 
							ralss | 
							⊢ ( 𝑎  ⊆  𝑋  →  ( ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎  ↔  ∀ 𝑏  ∈  𝑋 ( 𝑏  ∈  𝑎  →  𝐸  ∈  𝑎 ) ) )  | 
						
						
							| 3 | 
							
								1 2
							 | 
							syl | 
							⊢ ( 𝑎  ∈  𝒫  𝑋  →  ( ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎  ↔  ∀ 𝑏  ∈  𝑋 ( 𝑏  ∈  𝑎  →  𝐸  ∈  𝑎 ) ) )  | 
						
						
							| 4 | 
							
								
							 | 
							vex | 
							⊢ 𝑏  ∈  V  | 
						
						
							| 5 | 
							
								4
							 | 
							snss | 
							⊢ ( 𝑏  ∈  𝑎  ↔  { 𝑏 }  ⊆  𝑎 )  | 
						
						
							| 6 | 
							
								5
							 | 
							imbi1i | 
							⊢ ( ( 𝑏  ∈  𝑎  →  𝐸  ∈  𝑎 )  ↔  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) )  | 
						
						
							| 7 | 
							
								6
							 | 
							ralbii | 
							⊢ ( ∀ 𝑏  ∈  𝑋 ( 𝑏  ∈  𝑎  →  𝐸  ∈  𝑎 )  ↔  ∀ 𝑏  ∈  𝑋 ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) )  | 
						
						
							| 8 | 
							
								3 7
							 | 
							bitrdi | 
							⊢ ( 𝑎  ∈  𝒫  𝑋  →  ( ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎  ↔  ∀ 𝑏  ∈  𝑋 ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) ) )  | 
						
						
							| 9 | 
							
								8
							 | 
							rabbiia | 
							⊢ { 𝑎  ∈  𝒫  𝑋  ∣  ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎 }  =  { 𝑎  ∈  𝒫  𝑋  ∣  ∀ 𝑏  ∈  𝑋 ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  | 
						
						
							| 10 | 
							
								
							 | 
							riinrab | 
							⊢ ( 𝒫  𝑋  ∩  ∩  𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) } )  =  { 𝑎  ∈  𝒫  𝑋  ∣  ∀ 𝑏  ∈  𝑋 ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  | 
						
						
							| 11 | 
							
								9 10
							 | 
							eqtr4i | 
							⊢ { 𝑎  ∈  𝒫  𝑋  ∣  ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎 }  =  ( 𝒫  𝑋  ∩  ∩  𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) } )  | 
						
						
							| 12 | 
							
								
							 | 
							mreacs | 
							⊢ ( 𝑋  ∈  𝑉  →  ( ACS ‘ 𝑋 )  ∈  ( Moore ‘ 𝒫  𝑋 ) )  | 
						
						
							| 13 | 
							
								
							 | 
							simpll | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  ∧  𝐸  ∈  𝑋 )  →  𝑋  ∈  𝑉 )  | 
						
						
							| 14 | 
							
								
							 | 
							simpr | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  ∧  𝐸  ∈  𝑋 )  →  𝐸  ∈  𝑋 )  | 
						
						
							| 15 | 
							
								
							 | 
							snssi | 
							⊢ ( 𝑏  ∈  𝑋  →  { 𝑏 }  ⊆  𝑋 )  | 
						
						
							| 16 | 
							
								15
							 | 
							ad2antlr | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  ∧  𝐸  ∈  𝑋 )  →  { 𝑏 }  ⊆  𝑋 )  | 
						
						
							| 17 | 
							
								
							 | 
							snfi | 
							⊢ { 𝑏 }  ∈  Fin  | 
						
						
							| 18 | 
							
								17
							 | 
							a1i | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  ∧  𝐸  ∈  𝑋 )  →  { 𝑏 }  ∈  Fin )  | 
						
						
							| 19 | 
							
								
							 | 
							acsfn | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝐸  ∈  𝑋 )  ∧  ( { 𝑏 }  ⊆  𝑋  ∧  { 𝑏 }  ∈  Fin ) )  →  { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) )  | 
						
						
							| 20 | 
							
								13 14 16 18 19
							 | 
							syl22anc | 
							⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  ∧  𝐸  ∈  𝑋 )  →  { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) )  | 
						
						
							| 21 | 
							
								20
							 | 
							ex | 
							⊢ ( ( 𝑋  ∈  𝑉  ∧  𝑏  ∈  𝑋 )  →  ( 𝐸  ∈  𝑋  →  { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) ) )  | 
						
						
							| 22 | 
							
								21
							 | 
							ralimdva | 
							⊢ ( 𝑋  ∈  𝑉  →  ( ∀ 𝑏  ∈  𝑋 𝐸  ∈  𝑋  →  ∀ 𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) ) )  | 
						
						
							| 23 | 
							
								22
							 | 
							imp | 
							⊢ ( ( 𝑋  ∈  𝑉  ∧  ∀ 𝑏  ∈  𝑋 𝐸  ∈  𝑋 )  →  ∀ 𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) )  | 
						
						
							| 24 | 
							
								
							 | 
							mreriincl | 
							⊢ ( ( ( ACS ‘ 𝑋 )  ∈  ( Moore ‘ 𝒫  𝑋 )  ∧  ∀ 𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) }  ∈  ( ACS ‘ 𝑋 ) )  →  ( 𝒫  𝑋  ∩  ∩  𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) } )  ∈  ( ACS ‘ 𝑋 ) )  | 
						
						
							| 25 | 
							
								12 23 24
							 | 
							syl2an2r | 
							⊢ ( ( 𝑋  ∈  𝑉  ∧  ∀ 𝑏  ∈  𝑋 𝐸  ∈  𝑋 )  →  ( 𝒫  𝑋  ∩  ∩  𝑏  ∈  𝑋 { 𝑎  ∈  𝒫  𝑋  ∣  ( { 𝑏 }  ⊆  𝑎  →  𝐸  ∈  𝑎 ) } )  ∈  ( ACS ‘ 𝑋 ) )  | 
						
						
							| 26 | 
							
								11 25
							 | 
							eqeltrid | 
							⊢ ( ( 𝑋  ∈  𝑉  ∧  ∀ 𝑏  ∈  𝑋 𝐸  ∈  𝑋 )  →  { 𝑎  ∈  𝒫  𝑋  ∣  ∀ 𝑏  ∈  𝑎 𝐸  ∈  𝑎 }  ∈  ( ACS ‘ 𝑋 ) )  |