| Step | Hyp | Ref | Expression | 
						
							| 1 |  | txlly.1 |  |-  ( ( j e. A /\ k e. A ) -> ( j tX k ) e. A ) | 
						
							| 2 |  | llytop |  |-  ( R e. Locally A -> R e. Top ) | 
						
							| 3 |  | llytop |  |-  ( S e. Locally A -> S e. Top ) | 
						
							| 4 |  | txtop |  |-  ( ( R e. Top /\ S e. Top ) -> ( R tX S ) e. Top ) | 
						
							| 5 | 2 3 4 | syl2an |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( R tX S ) e. Top ) | 
						
							| 6 |  | eltx |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( x e. ( R tX S ) <-> A. y e. x E. u e. R E. v e. S ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) | 
						
							| 7 |  | simpll |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> R e. Locally A ) | 
						
							| 8 |  | simprll |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> u e. R ) | 
						
							| 9 |  | simprrl |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> y e. ( u X. v ) ) | 
						
							| 10 |  | xp1st |  |-  ( y e. ( u X. v ) -> ( 1st ` y ) e. u ) | 
						
							| 11 | 9 10 | syl |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> ( 1st ` y ) e. u ) | 
						
							| 12 |  | llyi |  |-  ( ( R e. Locally A /\ u e. R /\ ( 1st ` y ) e. u ) -> E. r e. R ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) ) | 
						
							| 13 | 7 8 11 12 | syl3anc |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> E. r e. R ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) ) | 
						
							| 14 |  | simplr |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> S e. Locally A ) | 
						
							| 15 |  | simprlr |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> v e. S ) | 
						
							| 16 |  | xp2nd |  |-  ( y e. ( u X. v ) -> ( 2nd ` y ) e. v ) | 
						
							| 17 | 9 16 | syl |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> ( 2nd ` y ) e. v ) | 
						
							| 18 |  | llyi |  |-  ( ( S e. Locally A /\ v e. S /\ ( 2nd ` y ) e. v ) -> E. s e. S ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) | 
						
							| 19 | 14 15 17 18 | syl3anc |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> E. s e. S ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) | 
						
							| 20 |  | reeanv |  |-  ( E. r e. R E. s e. S ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) <-> ( E. r e. R ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ E. s e. S ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) | 
						
							| 21 | 2 | ad3antrrr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> R e. Top ) | 
						
							| 22 | 3 | ad3antlr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> S e. Top ) | 
						
							| 23 |  | simprll |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> r e. R ) | 
						
							| 24 |  | simprlr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> s e. S ) | 
						
							| 25 |  | txopn |  |-  ( ( ( R e. Top /\ S e. Top ) /\ ( r e. R /\ s e. S ) ) -> ( r X. s ) e. ( R tX S ) ) | 
						
							| 26 | 21 22 23 24 25 | syl22anc |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( r X. s ) e. ( R tX S ) ) | 
						
							| 27 |  | simprl1 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> r C_ u ) | 
						
							| 28 |  | simprr1 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> s C_ v ) | 
						
							| 29 |  | xpss12 |  |-  ( ( r C_ u /\ s C_ v ) -> ( r X. s ) C_ ( u X. v ) ) | 
						
							| 30 | 27 28 29 | syl2anc |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( r X. s ) C_ ( u X. v ) ) | 
						
							| 31 |  | simprrr |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> ( u X. v ) C_ x ) | 
						
							| 32 | 30 31 | sylan9ssr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( r X. s ) C_ x ) | 
						
							| 33 |  | vex |  |-  x e. _V | 
						
							| 34 | 33 | elpw2 |  |-  ( ( r X. s ) e. ~P x <-> ( r X. s ) C_ x ) | 
						
							| 35 | 32 34 | sylibr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( r X. s ) e. ~P x ) | 
						
							| 36 | 26 35 | elind |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( r X. s ) e. ( ( R tX S ) i^i ~P x ) ) | 
						
							| 37 |  | 1st2nd2 |  |-  ( y e. ( u X. v ) -> y = <. ( 1st ` y ) , ( 2nd ` y ) >. ) | 
						
							| 38 | 9 37 | syl |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> y = <. ( 1st ` y ) , ( 2nd ` y ) >. ) | 
						
							| 39 | 38 | adantr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> y = <. ( 1st ` y ) , ( 2nd ` y ) >. ) | 
						
							| 40 |  | simprl2 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( 1st ` y ) e. r ) | 
						
							| 41 |  | simprr2 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( 2nd ` y ) e. s ) | 
						
							| 42 | 40 41 | opelxpd |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> <. ( 1st ` y ) , ( 2nd ` y ) >. e. ( r X. s ) ) | 
						
							| 43 | 42 | adantl |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> <. ( 1st ` y ) , ( 2nd ` y ) >. e. ( r X. s ) ) | 
						
							| 44 | 39 43 | eqeltrd |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> y e. ( r X. s ) ) | 
						
							| 45 |  | txrest |  |-  ( ( ( R e. Top /\ S e. Top ) /\ ( r e. R /\ s e. S ) ) -> ( ( R tX S ) |`t ( r X. s ) ) = ( ( R |`t r ) tX ( S |`t s ) ) ) | 
						
							| 46 | 21 22 23 24 45 | syl22anc |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( ( R tX S ) |`t ( r X. s ) ) = ( ( R |`t r ) tX ( S |`t s ) ) ) | 
						
							| 47 |  | simprl3 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( R |`t r ) e. A ) | 
						
							| 48 |  | simprr3 |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( S |`t s ) e. A ) | 
						
							| 49 | 1 | caovcl |  |-  ( ( ( R |`t r ) e. A /\ ( S |`t s ) e. A ) -> ( ( R |`t r ) tX ( S |`t s ) ) e. A ) | 
						
							| 50 | 47 48 49 | syl2anc |  |-  ( ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) -> ( ( R |`t r ) tX ( S |`t s ) ) e. A ) | 
						
							| 51 | 50 | adantl |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( ( R |`t r ) tX ( S |`t s ) ) e. A ) | 
						
							| 52 | 46 51 | eqeltrd |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> ( ( R tX S ) |`t ( r X. s ) ) e. A ) | 
						
							| 53 |  | eleq2 |  |-  ( z = ( r X. s ) -> ( y e. z <-> y e. ( r X. s ) ) ) | 
						
							| 54 |  | oveq2 |  |-  ( z = ( r X. s ) -> ( ( R tX S ) |`t z ) = ( ( R tX S ) |`t ( r X. s ) ) ) | 
						
							| 55 | 54 | eleq1d |  |-  ( z = ( r X. s ) -> ( ( ( R tX S ) |`t z ) e. A <-> ( ( R tX S ) |`t ( r X. s ) ) e. A ) ) | 
						
							| 56 | 53 55 | anbi12d |  |-  ( z = ( r X. s ) -> ( ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) <-> ( y e. ( r X. s ) /\ ( ( R tX S ) |`t ( r X. s ) ) e. A ) ) ) | 
						
							| 57 | 56 | rspcev |  |-  ( ( ( r X. s ) e. ( ( R tX S ) i^i ~P x ) /\ ( y e. ( r X. s ) /\ ( ( R tX S ) |`t ( r X. s ) ) e. A ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) | 
						
							| 58 | 36 44 52 57 | syl12anc |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( ( r e. R /\ s e. S ) /\ ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) | 
						
							| 59 | 58 | expr |  |-  ( ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) /\ ( r e. R /\ s e. S ) ) -> ( ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 60 | 59 | rexlimdvva |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> ( E. r e. R E. s e. S ( ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 61 | 20 60 | biimtrrid |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> ( ( E. r e. R ( r C_ u /\ ( 1st ` y ) e. r /\ ( R |`t r ) e. A ) /\ E. s e. S ( s C_ v /\ ( 2nd ` y ) e. s /\ ( S |`t s ) e. A ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 62 | 13 19 61 | mp2and |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( ( u e. R /\ v e. S ) /\ ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) ) ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) | 
						
							| 63 | 62 | expr |  |-  ( ( ( R e. Locally A /\ S e. Locally A ) /\ ( u e. R /\ v e. S ) ) -> ( ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 64 | 63 | rexlimdvva |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( E. u e. R E. v e. S ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) -> E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 65 | 64 | ralimdv |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( A. y e. x E. u e. R E. v e. S ( y e. ( u X. v ) /\ ( u X. v ) C_ x ) -> A. y e. x E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 66 | 6 65 | sylbid |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( x e. ( R tX S ) -> A. y e. x E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 67 | 66 | ralrimiv |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> A. x e. ( R tX S ) A. y e. x E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) | 
						
							| 68 |  | islly |  |-  ( ( R tX S ) e. Locally A <-> ( ( R tX S ) e. Top /\ A. x e. ( R tX S ) A. y e. x E. z e. ( ( R tX S ) i^i ~P x ) ( y e. z /\ ( ( R tX S ) |`t z ) e. A ) ) ) | 
						
							| 69 | 5 67 68 | sylanbrc |  |-  ( ( R e. Locally A /\ S e. Locally A ) -> ( R tX S ) e. Locally A ) |