| Step | Hyp | Ref | Expression | 
						
							| 1 |  | frxp.1 |  |-  T = { <. x , y >. | ( ( x e. ( A X. B ) /\ y e. ( A X. B ) ) /\ ( ( 1st ` x ) R ( 1st ` y ) \/ ( ( 1st ` x ) = ( 1st ` y ) /\ ( 2nd ` x ) S ( 2nd ` y ) ) ) ) } | 
						
							| 2 |  | ssn0 |  |-  ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> ( A X. B ) =/= (/) ) | 
						
							| 3 |  | xpnz |  |-  ( ( A =/= (/) /\ B =/= (/) ) <-> ( A X. B ) =/= (/) ) | 
						
							| 4 | 3 | biimpri |  |-  ( ( A X. B ) =/= (/) -> ( A =/= (/) /\ B =/= (/) ) ) | 
						
							| 5 | 4 | simprd |  |-  ( ( A X. B ) =/= (/) -> B =/= (/) ) | 
						
							| 6 | 2 5 | syl |  |-  ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> B =/= (/) ) | 
						
							| 7 |  | dmxp |  |-  ( B =/= (/) -> dom ( A X. B ) = A ) | 
						
							| 8 |  | dmss |  |-  ( s C_ ( A X. B ) -> dom s C_ dom ( A X. B ) ) | 
						
							| 9 |  | sseq2 |  |-  ( dom ( A X. B ) = A -> ( dom s C_ dom ( A X. B ) <-> dom s C_ A ) ) | 
						
							| 10 | 8 9 | imbitrid |  |-  ( dom ( A X. B ) = A -> ( s C_ ( A X. B ) -> dom s C_ A ) ) | 
						
							| 11 | 7 10 | syl |  |-  ( B =/= (/) -> ( s C_ ( A X. B ) -> dom s C_ A ) ) | 
						
							| 12 | 11 | impcom |  |-  ( ( s C_ ( A X. B ) /\ B =/= (/) ) -> dom s C_ A ) | 
						
							| 13 | 6 12 | syldan |  |-  ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> dom s C_ A ) | 
						
							| 14 |  | relxp |  |-  Rel ( A X. B ) | 
						
							| 15 |  | relss |  |-  ( s C_ ( A X. B ) -> ( Rel ( A X. B ) -> Rel s ) ) | 
						
							| 16 | 14 15 | mpi |  |-  ( s C_ ( A X. B ) -> Rel s ) | 
						
							| 17 |  | reldm0 |  |-  ( Rel s -> ( s = (/) <-> dom s = (/) ) ) | 
						
							| 18 | 16 17 | syl |  |-  ( s C_ ( A X. B ) -> ( s = (/) <-> dom s = (/) ) ) | 
						
							| 19 | 18 | necon3bid |  |-  ( s C_ ( A X. B ) -> ( s =/= (/) <-> dom s =/= (/) ) ) | 
						
							| 20 | 19 | biimpa |  |-  ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> dom s =/= (/) ) | 
						
							| 21 | 13 20 | jca |  |-  ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> ( dom s C_ A /\ dom s =/= (/) ) ) | 
						
							| 22 |  | df-fr |  |-  ( R Fr A <-> A. v ( ( v C_ A /\ v =/= (/) ) -> E. a e. v A. c e. v -. c R a ) ) | 
						
							| 23 |  | vex |  |-  s e. _V | 
						
							| 24 | 23 | dmex |  |-  dom s e. _V | 
						
							| 25 |  | sseq1 |  |-  ( v = dom s -> ( v C_ A <-> dom s C_ A ) ) | 
						
							| 26 |  | neeq1 |  |-  ( v = dom s -> ( v =/= (/) <-> dom s =/= (/) ) ) | 
						
							| 27 | 25 26 | anbi12d |  |-  ( v = dom s -> ( ( v C_ A /\ v =/= (/) ) <-> ( dom s C_ A /\ dom s =/= (/) ) ) ) | 
						
							| 28 |  | raleq |  |-  ( v = dom s -> ( A. c e. v -. c R a <-> A. c e. dom s -. c R a ) ) | 
						
							| 29 | 28 | rexeqbi1dv |  |-  ( v = dom s -> ( E. a e. v A. c e. v -. c R a <-> E. a e. dom s A. c e. dom s -. c R a ) ) | 
						
							| 30 | 27 29 | imbi12d |  |-  ( v = dom s -> ( ( ( v C_ A /\ v =/= (/) ) -> E. a e. v A. c e. v -. c R a ) <-> ( ( dom s C_ A /\ dom s =/= (/) ) -> E. a e. dom s A. c e. dom s -. c R a ) ) ) | 
						
							| 31 | 24 30 | spcv |  |-  ( A. v ( ( v C_ A /\ v =/= (/) ) -> E. a e. v A. c e. v -. c R a ) -> ( ( dom s C_ A /\ dom s =/= (/) ) -> E. a e. dom s A. c e. dom s -. c R a ) ) | 
						
							| 32 | 22 31 | sylbi |  |-  ( R Fr A -> ( ( dom s C_ A /\ dom s =/= (/) ) -> E. a e. dom s A. c e. dom s -. c R a ) ) | 
						
							| 33 | 21 32 | syl5 |  |-  ( R Fr A -> ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> E. a e. dom s A. c e. dom s -. c R a ) ) | 
						
							| 34 | 33 | adantr |  |-  ( ( R Fr A /\ S Fr B ) -> ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> E. a e. dom s A. c e. dom s -. c R a ) ) | 
						
							| 35 |  | imassrn |  |-  ( s " { a } ) C_ ran s | 
						
							| 36 |  | xpeq0 |  |-  ( ( A X. B ) = (/) <-> ( A = (/) \/ B = (/) ) ) | 
						
							| 37 | 36 | biimpri |  |-  ( ( A = (/) \/ B = (/) ) -> ( A X. B ) = (/) ) | 
						
							| 38 | 37 | orcs |  |-  ( A = (/) -> ( A X. B ) = (/) ) | 
						
							| 39 |  | sseq2 |  |-  ( ( A X. B ) = (/) -> ( s C_ ( A X. B ) <-> s C_ (/) ) ) | 
						
							| 40 |  | ss0 |  |-  ( s C_ (/) -> s = (/) ) | 
						
							| 41 | 39 40 | biimtrdi |  |-  ( ( A X. B ) = (/) -> ( s C_ ( A X. B ) -> s = (/) ) ) | 
						
							| 42 | 38 41 | syl |  |-  ( A = (/) -> ( s C_ ( A X. B ) -> s = (/) ) ) | 
						
							| 43 |  | rneq |  |-  ( s = (/) -> ran s = ran (/) ) | 
						
							| 44 |  | rn0 |  |-  ran (/) = (/) | 
						
							| 45 |  | 0ss |  |-  (/) C_ B | 
						
							| 46 | 44 45 | eqsstri |  |-  ran (/) C_ B | 
						
							| 47 | 43 46 | eqsstrdi |  |-  ( s = (/) -> ran s C_ B ) | 
						
							| 48 | 42 47 | syl6 |  |-  ( A = (/) -> ( s C_ ( A X. B ) -> ran s C_ B ) ) | 
						
							| 49 |  | rnxp |  |-  ( A =/= (/) -> ran ( A X. B ) = B ) | 
						
							| 50 |  | rnss |  |-  ( s C_ ( A X. B ) -> ran s C_ ran ( A X. B ) ) | 
						
							| 51 |  | sseq2 |  |-  ( ran ( A X. B ) = B -> ( ran s C_ ran ( A X. B ) <-> ran s C_ B ) ) | 
						
							| 52 | 50 51 | imbitrid |  |-  ( ran ( A X. B ) = B -> ( s C_ ( A X. B ) -> ran s C_ B ) ) | 
						
							| 53 | 49 52 | syl |  |-  ( A =/= (/) -> ( s C_ ( A X. B ) -> ran s C_ B ) ) | 
						
							| 54 | 48 53 | pm2.61ine |  |-  ( s C_ ( A X. B ) -> ran s C_ B ) | 
						
							| 55 | 35 54 | sstrid |  |-  ( s C_ ( A X. B ) -> ( s " { a } ) C_ B ) | 
						
							| 56 |  | vex |  |-  a e. _V | 
						
							| 57 | 56 | eldm |  |-  ( a e. dom s <-> E. b a s b ) | 
						
							| 58 |  | vex |  |-  b e. _V | 
						
							| 59 | 56 58 | elimasn |  |-  ( b e. ( s " { a } ) <-> <. a , b >. e. s ) | 
						
							| 60 |  | df-br |  |-  ( a s b <-> <. a , b >. e. s ) | 
						
							| 61 | 59 60 | bitr4i |  |-  ( b e. ( s " { a } ) <-> a s b ) | 
						
							| 62 |  | ne0i |  |-  ( b e. ( s " { a } ) -> ( s " { a } ) =/= (/) ) | 
						
							| 63 | 61 62 | sylbir |  |-  ( a s b -> ( s " { a } ) =/= (/) ) | 
						
							| 64 | 63 | exlimiv |  |-  ( E. b a s b -> ( s " { a } ) =/= (/) ) | 
						
							| 65 | 57 64 | sylbi |  |-  ( a e. dom s -> ( s " { a } ) =/= (/) ) | 
						
							| 66 |  | df-fr |  |-  ( S Fr B <-> A. v ( ( v C_ B /\ v =/= (/) ) -> E. b e. v A. d e. v -. d S b ) ) | 
						
							| 67 | 23 | imaex |  |-  ( s " { a } ) e. _V | 
						
							| 68 |  | sseq1 |  |-  ( v = ( s " { a } ) -> ( v C_ B <-> ( s " { a } ) C_ B ) ) | 
						
							| 69 |  | neeq1 |  |-  ( v = ( s " { a } ) -> ( v =/= (/) <-> ( s " { a } ) =/= (/) ) ) | 
						
							| 70 | 68 69 | anbi12d |  |-  ( v = ( s " { a } ) -> ( ( v C_ B /\ v =/= (/) ) <-> ( ( s " { a } ) C_ B /\ ( s " { a } ) =/= (/) ) ) ) | 
						
							| 71 |  | raleq |  |-  ( v = ( s " { a } ) -> ( A. d e. v -. d S b <-> A. d e. ( s " { a } ) -. d S b ) ) | 
						
							| 72 | 71 | rexeqbi1dv |  |-  ( v = ( s " { a } ) -> ( E. b e. v A. d e. v -. d S b <-> E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b ) ) | 
						
							| 73 | 70 72 | imbi12d |  |-  ( v = ( s " { a } ) -> ( ( ( v C_ B /\ v =/= (/) ) -> E. b e. v A. d e. v -. d S b ) <-> ( ( ( s " { a } ) C_ B /\ ( s " { a } ) =/= (/) ) -> E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b ) ) ) | 
						
							| 74 | 67 73 | spcv |  |-  ( A. v ( ( v C_ B /\ v =/= (/) ) -> E. b e. v A. d e. v -. d S b ) -> ( ( ( s " { a } ) C_ B /\ ( s " { a } ) =/= (/) ) -> E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b ) ) | 
						
							| 75 | 66 74 | sylbi |  |-  ( S Fr B -> ( ( ( s " { a } ) C_ B /\ ( s " { a } ) =/= (/) ) -> E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b ) ) | 
						
							| 76 | 55 65 75 | syl2ani |  |-  ( S Fr B -> ( ( s C_ ( A X. B ) /\ a e. dom s ) -> E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b ) ) | 
						
							| 77 |  | 1stdm |  |-  ( ( Rel s /\ w e. s ) -> ( 1st ` w ) e. dom s ) | 
						
							| 78 |  | breq1 |  |-  ( c = ( 1st ` w ) -> ( c R a <-> ( 1st ` w ) R a ) ) | 
						
							| 79 | 78 | notbid |  |-  ( c = ( 1st ` w ) -> ( -. c R a <-> -. ( 1st ` w ) R a ) ) | 
						
							| 80 | 79 | rspccv |  |-  ( A. c e. dom s -. c R a -> ( ( 1st ` w ) e. dom s -> -. ( 1st ` w ) R a ) ) | 
						
							| 81 | 77 80 | syl5 |  |-  ( A. c e. dom s -. c R a -> ( ( Rel s /\ w e. s ) -> -. ( 1st ` w ) R a ) ) | 
						
							| 82 | 81 | expd |  |-  ( A. c e. dom s -. c R a -> ( Rel s -> ( w e. s -> -. ( 1st ` w ) R a ) ) ) | 
						
							| 83 | 82 | impcom |  |-  ( ( Rel s /\ A. c e. dom s -. c R a ) -> ( w e. s -> -. ( 1st ` w ) R a ) ) | 
						
							| 84 | 83 | adantr |  |-  ( ( ( Rel s /\ A. c e. dom s -. c R a ) /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> -. ( 1st ` w ) R a ) ) | 
						
							| 85 |  | elrel |  |-  ( ( Rel s /\ w e. s ) -> E. t E. u w = <. t , u >. ) | 
						
							| 86 | 85 | ex |  |-  ( Rel s -> ( w e. s -> E. t E. u w = <. t , u >. ) ) | 
						
							| 87 | 86 | adantr |  |-  ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> E. t E. u w = <. t , u >. ) ) | 
						
							| 88 |  | vex |  |-  u e. _V | 
						
							| 89 | 56 88 | elimasn |  |-  ( u e. ( s " { a } ) <-> <. a , u >. e. s ) | 
						
							| 90 |  | breq1 |  |-  ( d = u -> ( d S b <-> u S b ) ) | 
						
							| 91 | 90 | notbid |  |-  ( d = u -> ( -. d S b <-> -. u S b ) ) | 
						
							| 92 | 91 | rspccv |  |-  ( A. d e. ( s " { a } ) -. d S b -> ( u e. ( s " { a } ) -> -. u S b ) ) | 
						
							| 93 | 89 92 | biimtrrid |  |-  ( A. d e. ( s " { a } ) -. d S b -> ( <. a , u >. e. s -> -. u S b ) ) | 
						
							| 94 | 93 | adantl |  |-  ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( <. a , u >. e. s -> -. u S b ) ) | 
						
							| 95 |  | opeq1 |  |-  ( t = a -> <. t , u >. = <. a , u >. ) | 
						
							| 96 | 95 | eleq1d |  |-  ( t = a -> ( <. t , u >. e. s <-> <. a , u >. e. s ) ) | 
						
							| 97 | 96 | imbi1d |  |-  ( t = a -> ( ( <. t , u >. e. s -> -. u S b ) <-> ( <. a , u >. e. s -> -. u S b ) ) ) | 
						
							| 98 | 94 97 | imbitrrid |  |-  ( t = a -> ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( <. t , u >. e. s -> -. u S b ) ) ) | 
						
							| 99 | 98 | com3l |  |-  ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( <. t , u >. e. s -> ( t = a -> -. u S b ) ) ) | 
						
							| 100 |  | eleq1 |  |-  ( w = <. t , u >. -> ( w e. s <-> <. t , u >. e. s ) ) | 
						
							| 101 |  | vex |  |-  t e. _V | 
						
							| 102 | 101 88 | op1std |  |-  ( w = <. t , u >. -> ( 1st ` w ) = t ) | 
						
							| 103 | 102 | eqeq1d |  |-  ( w = <. t , u >. -> ( ( 1st ` w ) = a <-> t = a ) ) | 
						
							| 104 | 101 88 | op2ndd |  |-  ( w = <. t , u >. -> ( 2nd ` w ) = u ) | 
						
							| 105 | 104 | breq1d |  |-  ( w = <. t , u >. -> ( ( 2nd ` w ) S b <-> u S b ) ) | 
						
							| 106 | 105 | notbid |  |-  ( w = <. t , u >. -> ( -. ( 2nd ` w ) S b <-> -. u S b ) ) | 
						
							| 107 | 103 106 | imbi12d |  |-  ( w = <. t , u >. -> ( ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) <-> ( t = a -> -. u S b ) ) ) | 
						
							| 108 | 100 107 | imbi12d |  |-  ( w = <. t , u >. -> ( ( w e. s -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) <-> ( <. t , u >. e. s -> ( t = a -> -. u S b ) ) ) ) | 
						
							| 109 | 99 108 | imbitrrid |  |-  ( w = <. t , u >. -> ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 110 | 109 | exlimivv |  |-  ( E. t E. u w = <. t , u >. -> ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 111 | 110 | com3l |  |-  ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( E. t E. u w = <. t , u >. -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 112 | 87 111 | mpdd |  |-  ( ( Rel s /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) | 
						
							| 113 | 112 | adantlr |  |-  ( ( ( Rel s /\ A. c e. dom s -. c R a ) /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) | 
						
							| 114 | 84 113 | jcad |  |-  ( ( ( Rel s /\ A. c e. dom s -. c R a ) /\ A. d e. ( s " { a } ) -. d S b ) -> ( w e. s -> ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 115 | 114 | ralrimiv |  |-  ( ( ( Rel s /\ A. c e. dom s -. c R a ) /\ A. d e. ( s " { a } ) -. d S b ) -> A. w e. s ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) | 
						
							| 116 | 115 | ex |  |-  ( ( Rel s /\ A. c e. dom s -. c R a ) -> ( A. d e. ( s " { a } ) -. d S b -> A. w e. s ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 117 | 16 116 | sylan |  |-  ( ( s C_ ( A X. B ) /\ A. c e. dom s -. c R a ) -> ( A. d e. ( s " { a } ) -. d S b -> A. w e. s ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 118 |  | olc |  |-  ( ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) -> ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 119 | 118 | ralimi |  |-  ( A. w e. s ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) -> A. w e. s ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 120 | 117 119 | syl6 |  |-  ( ( s C_ ( A X. B ) /\ A. c e. dom s -. c R a ) -> ( A. d e. ( s " { a } ) -. d S b -> A. w e. s ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) ) | 
						
							| 121 |  | ianor |  |-  ( -. ( ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) /\ ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) <-> ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ -. ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) ) | 
						
							| 122 |  | vex |  |-  w e. _V | 
						
							| 123 |  | opex |  |-  <. a , b >. e. _V | 
						
							| 124 |  | eleq1 |  |-  ( x = w -> ( x e. ( A X. B ) <-> w e. ( A X. B ) ) ) | 
						
							| 125 | 124 | anbi1d |  |-  ( x = w -> ( ( x e. ( A X. B ) /\ y e. ( A X. B ) ) <-> ( w e. ( A X. B ) /\ y e. ( A X. B ) ) ) ) | 
						
							| 126 |  | fveq2 |  |-  ( x = w -> ( 1st ` x ) = ( 1st ` w ) ) | 
						
							| 127 | 126 | breq1d |  |-  ( x = w -> ( ( 1st ` x ) R ( 1st ` y ) <-> ( 1st ` w ) R ( 1st ` y ) ) ) | 
						
							| 128 | 126 | eqeq1d |  |-  ( x = w -> ( ( 1st ` x ) = ( 1st ` y ) <-> ( 1st ` w ) = ( 1st ` y ) ) ) | 
						
							| 129 |  | fveq2 |  |-  ( x = w -> ( 2nd ` x ) = ( 2nd ` w ) ) | 
						
							| 130 | 129 | breq1d |  |-  ( x = w -> ( ( 2nd ` x ) S ( 2nd ` y ) <-> ( 2nd ` w ) S ( 2nd ` y ) ) ) | 
						
							| 131 | 128 130 | anbi12d |  |-  ( x = w -> ( ( ( 1st ` x ) = ( 1st ` y ) /\ ( 2nd ` x ) S ( 2nd ` y ) ) <-> ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) ) ) | 
						
							| 132 | 127 131 | orbi12d |  |-  ( x = w -> ( ( ( 1st ` x ) R ( 1st ` y ) \/ ( ( 1st ` x ) = ( 1st ` y ) /\ ( 2nd ` x ) S ( 2nd ` y ) ) ) <-> ( ( 1st ` w ) R ( 1st ` y ) \/ ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) ) ) ) | 
						
							| 133 | 125 132 | anbi12d |  |-  ( x = w -> ( ( ( x e. ( A X. B ) /\ y e. ( A X. B ) ) /\ ( ( 1st ` x ) R ( 1st ` y ) \/ ( ( 1st ` x ) = ( 1st ` y ) /\ ( 2nd ` x ) S ( 2nd ` y ) ) ) ) <-> ( ( w e. ( A X. B ) /\ y e. ( A X. B ) ) /\ ( ( 1st ` w ) R ( 1st ` y ) \/ ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) ) ) ) ) | 
						
							| 134 |  | eleq1 |  |-  ( y = <. a , b >. -> ( y e. ( A X. B ) <-> <. a , b >. e. ( A X. B ) ) ) | 
						
							| 135 | 134 | anbi2d |  |-  ( y = <. a , b >. -> ( ( w e. ( A X. B ) /\ y e. ( A X. B ) ) <-> ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) ) ) | 
						
							| 136 | 56 58 | op1std |  |-  ( y = <. a , b >. -> ( 1st ` y ) = a ) | 
						
							| 137 | 136 | breq2d |  |-  ( y = <. a , b >. -> ( ( 1st ` w ) R ( 1st ` y ) <-> ( 1st ` w ) R a ) ) | 
						
							| 138 | 136 | eqeq2d |  |-  ( y = <. a , b >. -> ( ( 1st ` w ) = ( 1st ` y ) <-> ( 1st ` w ) = a ) ) | 
						
							| 139 | 56 58 | op2ndd |  |-  ( y = <. a , b >. -> ( 2nd ` y ) = b ) | 
						
							| 140 | 139 | breq2d |  |-  ( y = <. a , b >. -> ( ( 2nd ` w ) S ( 2nd ` y ) <-> ( 2nd ` w ) S b ) ) | 
						
							| 141 | 138 140 | anbi12d |  |-  ( y = <. a , b >. -> ( ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) <-> ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) | 
						
							| 142 | 137 141 | orbi12d |  |-  ( y = <. a , b >. -> ( ( ( 1st ` w ) R ( 1st ` y ) \/ ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) ) <-> ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) ) | 
						
							| 143 | 135 142 | anbi12d |  |-  ( y = <. a , b >. -> ( ( ( w e. ( A X. B ) /\ y e. ( A X. B ) ) /\ ( ( 1st ` w ) R ( 1st ` y ) \/ ( ( 1st ` w ) = ( 1st ` y ) /\ ( 2nd ` w ) S ( 2nd ` y ) ) ) ) <-> ( ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) /\ ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) ) ) | 
						
							| 144 | 122 123 133 143 1 | brab |  |-  ( w T <. a , b >. <-> ( ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) /\ ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) ) | 
						
							| 145 | 121 144 | xchnxbir |  |-  ( -. w T <. a , b >. <-> ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ -. ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) ) | 
						
							| 146 |  | ioran |  |-  ( -. ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) <-> ( -. ( 1st ` w ) R a /\ -. ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) | 
						
							| 147 |  | ianor |  |-  ( -. ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) <-> ( -. ( 1st ` w ) = a \/ -. ( 2nd ` w ) S b ) ) | 
						
							| 148 |  | pm4.62 |  |-  ( ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) <-> ( -. ( 1st ` w ) = a \/ -. ( 2nd ` w ) S b ) ) | 
						
							| 149 | 147 148 | bitr4i |  |-  ( -. ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) <-> ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) | 
						
							| 150 | 149 | anbi2i |  |-  ( ( -. ( 1st ` w ) R a /\ -. ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) <-> ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) | 
						
							| 151 | 146 150 | bitri |  |-  ( -. ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) <-> ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) | 
						
							| 152 | 151 | orbi2i |  |-  ( ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ -. ( ( 1st ` w ) R a \/ ( ( 1st ` w ) = a /\ ( 2nd ` w ) S b ) ) ) <-> ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 153 | 145 152 | bitri |  |-  ( -. w T <. a , b >. <-> ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 154 | 153 | ralbii |  |-  ( A. w e. s -. w T <. a , b >. <-> A. w e. s ( -. ( w e. ( A X. B ) /\ <. a , b >. e. ( A X. B ) ) \/ ( -. ( 1st ` w ) R a /\ ( ( 1st ` w ) = a -> -. ( 2nd ` w ) S b ) ) ) ) | 
						
							| 155 | 120 154 | imbitrrdi |  |-  ( ( s C_ ( A X. B ) /\ A. c e. dom s -. c R a ) -> ( A. d e. ( s " { a } ) -. d S b -> A. w e. s -. w T <. a , b >. ) ) | 
						
							| 156 | 155 | reximdv |  |-  ( ( s C_ ( A X. B ) /\ A. c e. dom s -. c R a ) -> ( E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) | 
						
							| 157 | 156 | ex |  |-  ( s C_ ( A X. B ) -> ( A. c e. dom s -. c R a -> ( E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) ) | 
						
							| 158 | 157 | com23 |  |-  ( s C_ ( A X. B ) -> ( E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b -> ( A. c e. dom s -. c R a -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) ) | 
						
							| 159 | 158 | adantr |  |-  ( ( s C_ ( A X. B ) /\ a e. dom s ) -> ( E. b e. ( s " { a } ) A. d e. ( s " { a } ) -. d S b -> ( A. c e. dom s -. c R a -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) ) | 
						
							| 160 | 76 159 | sylcom |  |-  ( S Fr B -> ( ( s C_ ( A X. B ) /\ a e. dom s ) -> ( A. c e. dom s -. c R a -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) ) | 
						
							| 161 | 160 | impl |  |-  ( ( ( S Fr B /\ s C_ ( A X. B ) ) /\ a e. dom s ) -> ( A. c e. dom s -. c R a -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) | 
						
							| 162 | 161 | expimpd |  |-  ( ( S Fr B /\ s C_ ( A X. B ) ) -> ( ( a e. dom s /\ A. c e. dom s -. c R a ) -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) | 
						
							| 163 | 162 | 3adant3 |  |-  ( ( S Fr B /\ s C_ ( A X. B ) /\ s =/= (/) ) -> ( ( a e. dom s /\ A. c e. dom s -. c R a ) -> E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. ) ) | 
						
							| 164 |  | resss |  |-  ( s |` { a } ) C_ s | 
						
							| 165 |  | df-rex |  |-  ( E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. <-> E. b ( b e. ( s " { a } ) /\ A. w e. s -. w T <. a , b >. ) ) | 
						
							| 166 |  | eqid |  |-  <. a , b >. = <. a , b >. | 
						
							| 167 |  | eqeq1 |  |-  ( z = <. a , b >. -> ( z = <. a , b >. <-> <. a , b >. = <. a , b >. ) ) | 
						
							| 168 |  | breq2 |  |-  ( z = <. a , b >. -> ( w T z <-> w T <. a , b >. ) ) | 
						
							| 169 | 168 | notbid |  |-  ( z = <. a , b >. -> ( -. w T z <-> -. w T <. a , b >. ) ) | 
						
							| 170 | 169 | ralbidv |  |-  ( z = <. a , b >. -> ( A. w e. s -. w T z <-> A. w e. s -. w T <. a , b >. ) ) | 
						
							| 171 | 170 | anbi2d |  |-  ( z = <. a , b >. -> ( ( <. a , b >. e. s /\ A. w e. s -. w T z ) <-> ( <. a , b >. e. s /\ A. w e. s -. w T <. a , b >. ) ) ) | 
						
							| 172 | 167 171 | anbi12d |  |-  ( z = <. a , b >. -> ( ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) <-> ( <. a , b >. = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T <. a , b >. ) ) ) ) | 
						
							| 173 | 123 172 | spcev |  |-  ( ( <. a , b >. = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T <. a , b >. ) ) -> E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 174 | 166 173 | mpan |  |-  ( ( <. a , b >. e. s /\ A. w e. s -. w T <. a , b >. ) -> E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 175 | 59 174 | sylanb |  |-  ( ( b e. ( s " { a } ) /\ A. w e. s -. w T <. a , b >. ) -> E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 176 | 175 | eximi |  |-  ( E. b ( b e. ( s " { a } ) /\ A. w e. s -. w T <. a , b >. ) -> E. b E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 177 | 165 176 | sylbi |  |-  ( E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. -> E. b E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 178 |  | excom |  |-  ( E. b E. z ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) <-> E. z E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 179 | 177 178 | sylib |  |-  ( E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. -> E. z E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 180 |  | df-rex |  |-  ( E. z e. ( s |` { a } ) A. w e. s -. w T z <-> E. z ( z e. ( s |` { a } ) /\ A. w e. s -. w T z ) ) | 
						
							| 181 | 56 | elsnres |  |-  ( z e. ( s |` { a } ) <-> E. b ( z = <. a , b >. /\ <. a , b >. e. s ) ) | 
						
							| 182 | 181 | anbi1i |  |-  ( ( z e. ( s |` { a } ) /\ A. w e. s -. w T z ) <-> ( E. b ( z = <. a , b >. /\ <. a , b >. e. s ) /\ A. w e. s -. w T z ) ) | 
						
							| 183 |  | 19.41v |  |-  ( E. b ( ( z = <. a , b >. /\ <. a , b >. e. s ) /\ A. w e. s -. w T z ) <-> ( E. b ( z = <. a , b >. /\ <. a , b >. e. s ) /\ A. w e. s -. w T z ) ) | 
						
							| 184 |  | anass |  |-  ( ( ( z = <. a , b >. /\ <. a , b >. e. s ) /\ A. w e. s -. w T z ) <-> ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 185 | 184 | exbii |  |-  ( E. b ( ( z = <. a , b >. /\ <. a , b >. e. s ) /\ A. w e. s -. w T z ) <-> E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 186 | 182 183 185 | 3bitr2i |  |-  ( ( z e. ( s |` { a } ) /\ A. w e. s -. w T z ) <-> E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 187 | 186 | exbii |  |-  ( E. z ( z e. ( s |` { a } ) /\ A. w e. s -. w T z ) <-> E. z E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 188 | 180 187 | bitri |  |-  ( E. z e. ( s |` { a } ) A. w e. s -. w T z <-> E. z E. b ( z = <. a , b >. /\ ( <. a , b >. e. s /\ A. w e. s -. w T z ) ) ) | 
						
							| 189 | 179 188 | sylibr |  |-  ( E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. -> E. z e. ( s |` { a } ) A. w e. s -. w T z ) | 
						
							| 190 |  | ssrexv |  |-  ( ( s |` { a } ) C_ s -> ( E. z e. ( s |` { a } ) A. w e. s -. w T z -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 191 | 164 189 190 | mpsyl |  |-  ( E. b e. ( s " { a } ) A. w e. s -. w T <. a , b >. -> E. z e. s A. w e. s -. w T z ) | 
						
							| 192 | 163 191 | syl6 |  |-  ( ( S Fr B /\ s C_ ( A X. B ) /\ s =/= (/) ) -> ( ( a e. dom s /\ A. c e. dom s -. c R a ) -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 193 | 192 | expd |  |-  ( ( S Fr B /\ s C_ ( A X. B ) /\ s =/= (/) ) -> ( a e. dom s -> ( A. c e. dom s -. c R a -> E. z e. s A. w e. s -. w T z ) ) ) | 
						
							| 194 | 193 | rexlimdv |  |-  ( ( S Fr B /\ s C_ ( A X. B ) /\ s =/= (/) ) -> ( E. a e. dom s A. c e. dom s -. c R a -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 195 | 194 | 3expib |  |-  ( S Fr B -> ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> ( E. a e. dom s A. c e. dom s -. c R a -> E. z e. s A. w e. s -. w T z ) ) ) | 
						
							| 196 | 195 | adantl |  |-  ( ( R Fr A /\ S Fr B ) -> ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> ( E. a e. dom s A. c e. dom s -. c R a -> E. z e. s A. w e. s -. w T z ) ) ) | 
						
							| 197 | 34 196 | mpdd |  |-  ( ( R Fr A /\ S Fr B ) -> ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 198 | 197 | alrimiv |  |-  ( ( R Fr A /\ S Fr B ) -> A. s ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 199 |  | df-fr |  |-  ( T Fr ( A X. B ) <-> A. s ( ( s C_ ( A X. B ) /\ s =/= (/) ) -> E. z e. s A. w e. s -. w T z ) ) | 
						
							| 200 | 198 199 | sylibr |  |-  ( ( R Fr A /\ S Fr B ) -> T Fr ( A X. B ) ) |