| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							canthwe.1 | 
							 |-  O = { <. x , r >. | ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) } | 
						
						
							| 2 | 
							
								
							 | 
							simp1 | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> x C_ A )  | 
						
						
							| 3 | 
							
								
							 | 
							velpw | 
							 |-  ( x e. ~P A <-> x C_ A )  | 
						
						
							| 4 | 
							
								2 3
							 | 
							sylibr | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> x e. ~P A )  | 
						
						
							| 5 | 
							
								
							 | 
							simp2 | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> r C_ ( x X. x ) )  | 
						
						
							| 6 | 
							
								
							 | 
							xpss12 | 
							 |-  ( ( x C_ A /\ x C_ A ) -> ( x X. x ) C_ ( A X. A ) )  | 
						
						
							| 7 | 
							
								2 2 6
							 | 
							syl2anc | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> ( x X. x ) C_ ( A X. A ) )  | 
						
						
							| 8 | 
							
								5 7
							 | 
							sstrd | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> r C_ ( A X. A ) )  | 
						
						
							| 9 | 
							
								
							 | 
							velpw | 
							 |-  ( r e. ~P ( A X. A ) <-> r C_ ( A X. A ) )  | 
						
						
							| 10 | 
							
								8 9
							 | 
							sylibr | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> r e. ~P ( A X. A ) )  | 
						
						
							| 11 | 
							
								4 10
							 | 
							jca | 
							 |-  ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) -> ( x e. ~P A /\ r e. ~P ( A X. A ) ) )  | 
						
						
							| 12 | 
							
								11
							 | 
							ssopab2i | 
							 |-  { <. x , r >. | ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) } C_ { <. x , r >. | ( x e. ~P A /\ r e. ~P ( A X. A ) ) } | 
						
						
							| 13 | 
							
								
							 | 
							df-xp | 
							 |-  ( ~P A X. ~P ( A X. A ) ) = { <. x , r >. | ( x e. ~P A /\ r e. ~P ( A X. A ) ) } | 
						
						
							| 14 | 
							
								12 1 13
							 | 
							3sstr4i | 
							 |-  O C_ ( ~P A X. ~P ( A X. A ) )  | 
						
						
							| 15 | 
							
								
							 | 
							pwexg | 
							 |-  ( A e. V -> ~P A e. _V )  | 
						
						
							| 16 | 
							
								
							 | 
							sqxpexg | 
							 |-  ( A e. V -> ( A X. A ) e. _V )  | 
						
						
							| 17 | 
							
								16
							 | 
							pwexd | 
							 |-  ( A e. V -> ~P ( A X. A ) e. _V )  | 
						
						
							| 18 | 
							
								15 17
							 | 
							xpexd | 
							 |-  ( A e. V -> ( ~P A X. ~P ( A X. A ) ) e. _V )  | 
						
						
							| 19 | 
							
								
							 | 
							ssexg | 
							 |-  ( ( O C_ ( ~P A X. ~P ( A X. A ) ) /\ ( ~P A X. ~P ( A X. A ) ) e. _V ) -> O e. _V )  | 
						
						
							| 20 | 
							
								14 18 19
							 | 
							sylancr | 
							 |-  ( A e. V -> O e. _V )  | 
						
						
							| 21 | 
							
								
							 | 
							simpr | 
							 |-  ( ( A e. V /\ u e. A ) -> u e. A )  | 
						
						
							| 22 | 
							
								21
							 | 
							snssd | 
							 |-  ( ( A e. V /\ u e. A ) -> { u } C_ A ) | 
						
						
							| 23 | 
							
								
							 | 
							0ss | 
							 |-  (/) C_ ( { u } X. { u } ) | 
						
						
							| 24 | 
							
								23
							 | 
							a1i | 
							 |-  ( ( A e. V /\ u e. A ) -> (/) C_ ( { u } X. { u } ) ) | 
						
						
							| 25 | 
							
								
							 | 
							rel0 | 
							 |-  Rel (/)  | 
						
						
							| 26 | 
							
								
							 | 
							br0 | 
							 |-  -. u (/) u  | 
						
						
							| 27 | 
							
								
							 | 
							wesn | 
							 |-  ( Rel (/) -> ( (/) We { u } <-> -. u (/) u ) ) | 
						
						
							| 28 | 
							
								26 27
							 | 
							mpbiri | 
							 |-  ( Rel (/) -> (/) We { u } ) | 
						
						
							| 29 | 
							
								25 28
							 | 
							mp1i | 
							 |-  ( ( A e. V /\ u e. A ) -> (/) We { u } ) | 
						
						
							| 30 | 
							
								
							 | 
							vsnex | 
							 |-  { u } e. _V | 
						
						
							| 31 | 
							
								
							 | 
							0ex | 
							 |-  (/) e. _V  | 
						
						
							| 32 | 
							
								
							 | 
							simpl | 
							 |-  ( ( x = { u } /\ r = (/) ) -> x = { u } ) | 
						
						
							| 33 | 
							
								32
							 | 
							sseq1d | 
							 |-  ( ( x = { u } /\ r = (/) ) -> ( x C_ A <-> { u } C_ A ) ) | 
						
						
							| 34 | 
							
								
							 | 
							simpr | 
							 |-  ( ( x = { u } /\ r = (/) ) -> r = (/) ) | 
						
						
							| 35 | 
							
								32
							 | 
							sqxpeqd | 
							 |-  ( ( x = { u } /\ r = (/) ) -> ( x X. x ) = ( { u } X. { u } ) ) | 
						
						
							| 36 | 
							
								34 35
							 | 
							sseq12d | 
							 |-  ( ( x = { u } /\ r = (/) ) -> ( r C_ ( x X. x ) <-> (/) C_ ( { u } X. { u } ) ) ) | 
						
						
							| 37 | 
							
								34 32
							 | 
							weeq12d | 
							 |-  ( ( x = { u } /\ r = (/) ) -> ( r We x <-> (/) We { u } ) ) | 
						
						
							| 38 | 
							
								33 36 37
							 | 
							3anbi123d | 
							 |-  ( ( x = { u } /\ r = (/) ) -> ( ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) <-> ( { u } C_ A /\ (/) C_ ( { u } X. { u } ) /\ (/) We { u } ) ) ) | 
						
						
							| 39 | 
							
								30 31 38
							 | 
							opelopaba | 
							 |-  ( <. { u } , (/) >. e. { <. x , r >. | ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) } <-> ( { u } C_ A /\ (/) C_ ( { u } X. { u } ) /\ (/) We { u } ) ) | 
						
						
							| 40 | 
							
								22 24 29 39
							 | 
							syl3anbrc | 
							 |-  ( ( A e. V /\ u e. A ) -> <. { u } , (/) >. e. { <. x , r >. | ( x C_ A /\ r C_ ( x X. x ) /\ r We x ) } ) | 
						
						
							| 41 | 
							
								40 1
							 | 
							eleqtrrdi | 
							 |-  ( ( A e. V /\ u e. A ) -> <. { u } , (/) >. e. O ) | 
						
						
							| 42 | 
							
								41
							 | 
							ex | 
							 |-  ( A e. V -> ( u e. A -> <. { u } , (/) >. e. O ) ) | 
						
						
							| 43 | 
							
								
							 | 
							eqid | 
							 |-  (/) = (/)  | 
						
						
							| 44 | 
							
								
							 | 
							vsnex | 
							 |-  { v } e. _V | 
						
						
							| 45 | 
							
								44 31
							 | 
							opth2 | 
							 |-  ( <. { u } , (/) >. = <. { v } , (/) >. <-> ( { u } = { v } /\ (/) = (/) ) ) | 
						
						
							| 46 | 
							
								43 45
							 | 
							mpbiran2 | 
							 |-  ( <. { u } , (/) >. = <. { v } , (/) >. <-> { u } = { v } ) | 
						
						
							| 47 | 
							
								
							 | 
							sneqbg | 
							 |-  ( u e. _V -> ( { u } = { v } <-> u = v ) ) | 
						
						
							| 48 | 
							
								47
							 | 
							elv | 
							 |-  ( { u } = { v } <-> u = v ) | 
						
						
							| 49 | 
							
								46 48
							 | 
							bitri | 
							 |-  ( <. { u } , (/) >. = <. { v } , (/) >. <-> u = v ) | 
						
						
							| 50 | 
							
								49
							 | 
							2a1i | 
							 |-  ( A e. V -> ( ( u e. A /\ v e. A ) -> ( <. { u } , (/) >. = <. { v } , (/) >. <-> u = v ) ) ) | 
						
						
							| 51 | 
							
								42 50
							 | 
							dom2d | 
							 |-  ( A e. V -> ( O e. _V -> A ~<_ O ) )  | 
						
						
							| 52 | 
							
								20 51
							 | 
							mpd | 
							 |-  ( A e. V -> A ~<_ O )  | 
						
						
							| 53 | 
							
								
							 | 
							eqid | 
							 |-  { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } = { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } | 
						
						
							| 54 | 
							
								53
							 | 
							fpwwe2cbv | 
							 |-  { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } = { <. x , r >. | ( ( x C_ A /\ r C_ ( x X. x ) ) /\ ( r We x /\ A. y e. x [. ( `' r " { y } ) / w ]. ( w f ( r i^i ( w X. w ) ) ) = y ) ) } | 
						
						
							| 55 | 
							
								
							 | 
							eqid | 
							 |-  U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } = U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } | 
						
						
							| 56 | 
							
								
							 | 
							eqid | 
							 |-  ( `' ( { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ` U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ) " { ( U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } f ( { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ` U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ) ) } ) = ( `' ( { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ` U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ) " { ( U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } f ( { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ` U. dom { <. a , s >. | ( ( a C_ A /\ s C_ ( a X. a ) ) /\ ( s We a /\ A. z e. a [. ( `' s " { z } ) / v ]. ( v f ( s i^i ( v X. v ) ) ) = z ) ) } ) ) } ) | 
						
						
							| 57 | 
							
								1 54 55 56
							 | 
							canthwelem | 
							 |-  ( A e. V -> -. f : O -1-1-> A )  | 
						
						
							| 58 | 
							
								
							 | 
							f1of1 | 
							 |-  ( f : O -1-1-onto-> A -> f : O -1-1-> A )  | 
						
						
							| 59 | 
							
								57 58
							 | 
							nsyl | 
							 |-  ( A e. V -> -. f : O -1-1-onto-> A )  | 
						
						
							| 60 | 
							
								59
							 | 
							nexdv | 
							 |-  ( A e. V -> -. E. f f : O -1-1-onto-> A )  | 
						
						
							| 61 | 
							
								
							 | 
							ensym | 
							 |-  ( A ~~ O -> O ~~ A )  | 
						
						
							| 62 | 
							
								
							 | 
							bren | 
							 |-  ( O ~~ A <-> E. f f : O -1-1-onto-> A )  | 
						
						
							| 63 | 
							
								61 62
							 | 
							sylib | 
							 |-  ( A ~~ O -> E. f f : O -1-1-onto-> A )  | 
						
						
							| 64 | 
							
								60 63
							 | 
							nsyl | 
							 |-  ( A e. V -> -. A ~~ O )  | 
						
						
							| 65 | 
							
								
							 | 
							brsdom | 
							 |-  ( A ~< O <-> ( A ~<_ O /\ -. A ~~ O ) )  | 
						
						
							| 66 | 
							
								52 64 65
							 | 
							sylanbrc | 
							 |-  ( A e. V -> A ~< O )  |