| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mulsunif2.1 |  |-  ( ph -> L < | 
						
							| 2 |  | mulsunif2.2 |  |-  ( ph -> M < | 
						
							| 3 |  | mulsunif2.3 |  |-  ( ph -> A = ( L |s R ) ) | 
						
							| 4 |  | mulsunif2.4 |  |-  ( ph -> B = ( M |s S ) ) | 
						
							| 5 | 1 2 3 4 | mulsunif2lem |  |-  ( ph -> ( A x.s B ) = ( ( { e | E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) } u. { f | E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) } ) |s ( { g | E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) } u. { h | E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) } ) ) ) | 
						
							| 6 |  | eqeq1 |  |-  ( e = a -> ( e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) <-> a = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) ) ) | 
						
							| 7 | 6 | 2rexbidv |  |-  ( e = a -> ( E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) <-> E. i e. L E. j e. M a = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) ) ) | 
						
							| 8 |  | oveq2 |  |-  ( i = p -> ( A -s i ) = ( A -s p ) ) | 
						
							| 9 | 8 | oveq1d |  |-  ( i = p -> ( ( A -s i ) x.s ( B -s j ) ) = ( ( A -s p ) x.s ( B -s j ) ) ) | 
						
							| 10 | 9 | oveq2d |  |-  ( i = p -> ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s j ) ) ) ) | 
						
							| 11 | 10 | eqeq2d |  |-  ( i = p -> ( a = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) <-> a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s j ) ) ) ) ) | 
						
							| 12 |  | oveq2 |  |-  ( j = q -> ( B -s j ) = ( B -s q ) ) | 
						
							| 13 | 12 | oveq2d |  |-  ( j = q -> ( ( A -s p ) x.s ( B -s j ) ) = ( ( A -s p ) x.s ( B -s q ) ) ) | 
						
							| 14 | 13 | oveq2d |  |-  ( j = q -> ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s j ) ) ) = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) ) | 
						
							| 15 | 14 | eqeq2d |  |-  ( j = q -> ( a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s j ) ) ) <-> a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) ) ) | 
						
							| 16 | 11 15 | cbvrex2vw |  |-  ( E. i e. L E. j e. M a = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) <-> E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) ) | 
						
							| 17 | 7 16 | bitrdi |  |-  ( e = a -> ( E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) <-> E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) ) ) | 
						
							| 18 | 17 | cbvabv |  |-  { e | E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) } = { a | E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) } | 
						
							| 19 |  | eqeq1 |  |-  ( f = b -> ( f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) <-> b = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) ) ) | 
						
							| 20 | 19 | 2rexbidv |  |-  ( f = b -> ( E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) <-> E. k e. R E. l e. S b = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) ) ) | 
						
							| 21 |  | oveq1 |  |-  ( k = r -> ( k -s A ) = ( r -s A ) ) | 
						
							| 22 | 21 | oveq1d |  |-  ( k = r -> ( ( k -s A ) x.s ( l -s B ) ) = ( ( r -s A ) x.s ( l -s B ) ) ) | 
						
							| 23 | 22 | oveq2d |  |-  ( k = r -> ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) = ( ( A x.s B ) -s ( ( r -s A ) x.s ( l -s B ) ) ) ) | 
						
							| 24 | 23 | eqeq2d |  |-  ( k = r -> ( b = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) <-> b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( l -s B ) ) ) ) ) | 
						
							| 25 |  | oveq1 |  |-  ( l = s -> ( l -s B ) = ( s -s B ) ) | 
						
							| 26 | 25 | oveq2d |  |-  ( l = s -> ( ( r -s A ) x.s ( l -s B ) ) = ( ( r -s A ) x.s ( s -s B ) ) ) | 
						
							| 27 | 26 | oveq2d |  |-  ( l = s -> ( ( A x.s B ) -s ( ( r -s A ) x.s ( l -s B ) ) ) = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) ) | 
						
							| 28 | 27 | eqeq2d |  |-  ( l = s -> ( b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( l -s B ) ) ) <-> b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) ) ) | 
						
							| 29 | 24 28 | cbvrex2vw |  |-  ( E. k e. R E. l e. S b = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) <-> E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) ) | 
						
							| 30 | 20 29 | bitrdi |  |-  ( f = b -> ( E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) <-> E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) ) ) | 
						
							| 31 | 30 | cbvabv |  |-  { f | E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) } = { b | E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) } | 
						
							| 32 | 18 31 | uneq12i |  |-  ( { e | E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) } u. { f | E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) } ) = ( { a | E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) } u. { b | E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) } ) | 
						
							| 33 |  | eqeq1 |  |-  ( g = c -> ( g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) <-> c = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) ) ) | 
						
							| 34 | 33 | 2rexbidv |  |-  ( g = c -> ( E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) <-> E. m e. L E. n e. S c = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) ) ) | 
						
							| 35 |  | oveq2 |  |-  ( m = t -> ( A -s m ) = ( A -s t ) ) | 
						
							| 36 | 35 | oveq1d |  |-  ( m = t -> ( ( A -s m ) x.s ( n -s B ) ) = ( ( A -s t ) x.s ( n -s B ) ) ) | 
						
							| 37 | 36 | oveq2d |  |-  ( m = t -> ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) = ( ( A x.s B ) +s ( ( A -s t ) x.s ( n -s B ) ) ) ) | 
						
							| 38 | 37 | eqeq2d |  |-  ( m = t -> ( c = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) <-> c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( n -s B ) ) ) ) ) | 
						
							| 39 |  | oveq1 |  |-  ( n = u -> ( n -s B ) = ( u -s B ) ) | 
						
							| 40 | 39 | oveq2d |  |-  ( n = u -> ( ( A -s t ) x.s ( n -s B ) ) = ( ( A -s t ) x.s ( u -s B ) ) ) | 
						
							| 41 | 40 | oveq2d |  |-  ( n = u -> ( ( A x.s B ) +s ( ( A -s t ) x.s ( n -s B ) ) ) = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) ) | 
						
							| 42 | 41 | eqeq2d |  |-  ( n = u -> ( c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( n -s B ) ) ) <-> c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) ) ) | 
						
							| 43 | 38 42 | cbvrex2vw |  |-  ( E. m e. L E. n e. S c = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) <-> E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) ) | 
						
							| 44 | 34 43 | bitrdi |  |-  ( g = c -> ( E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) <-> E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) ) ) | 
						
							| 45 | 44 | cbvabv |  |-  { g | E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) } = { c | E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) } | 
						
							| 46 |  | eqeq1 |  |-  ( h = d -> ( h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) <-> d = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) ) ) | 
						
							| 47 | 46 | 2rexbidv |  |-  ( h = d -> ( E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) <-> E. o e. R E. x e. M d = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) ) ) | 
						
							| 48 |  | oveq1 |  |-  ( o = v -> ( o -s A ) = ( v -s A ) ) | 
						
							| 49 | 48 | oveq1d |  |-  ( o = v -> ( ( o -s A ) x.s ( B -s x ) ) = ( ( v -s A ) x.s ( B -s x ) ) ) | 
						
							| 50 | 49 | oveq2d |  |-  ( o = v -> ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s x ) ) ) ) | 
						
							| 51 | 50 | eqeq2d |  |-  ( o = v -> ( d = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) <-> d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s x ) ) ) ) ) | 
						
							| 52 |  | oveq2 |  |-  ( x = w -> ( B -s x ) = ( B -s w ) ) | 
						
							| 53 | 52 | oveq2d |  |-  ( x = w -> ( ( v -s A ) x.s ( B -s x ) ) = ( ( v -s A ) x.s ( B -s w ) ) ) | 
						
							| 54 | 53 | oveq2d |  |-  ( x = w -> ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s x ) ) ) = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) ) | 
						
							| 55 | 54 | eqeq2d |  |-  ( x = w -> ( d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s x ) ) ) <-> d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) ) ) | 
						
							| 56 | 51 55 | cbvrex2vw |  |-  ( E. o e. R E. x e. M d = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) <-> E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) ) | 
						
							| 57 | 47 56 | bitrdi |  |-  ( h = d -> ( E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) <-> E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) ) ) | 
						
							| 58 | 57 | cbvabv |  |-  { h | E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) } = { d | E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) } | 
						
							| 59 | 45 58 | uneq12i |  |-  ( { g | E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) } u. { h | E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) } ) = ( { c | E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) } u. { d | E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) } ) | 
						
							| 60 | 32 59 | oveq12i |  |-  ( ( { e | E. i e. L E. j e. M e = ( ( A x.s B ) -s ( ( A -s i ) x.s ( B -s j ) ) ) } u. { f | E. k e. R E. l e. S f = ( ( A x.s B ) -s ( ( k -s A ) x.s ( l -s B ) ) ) } ) |s ( { g | E. m e. L E. n e. S g = ( ( A x.s B ) +s ( ( A -s m ) x.s ( n -s B ) ) ) } u. { h | E. o e. R E. x e. M h = ( ( A x.s B ) +s ( ( o -s A ) x.s ( B -s x ) ) ) } ) ) = ( ( { a | E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) } u. { b | E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) } ) |s ( { c | E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) } u. { d | E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) } ) ) | 
						
							| 61 | 5 60 | eqtrdi |  |-  ( ph -> ( A x.s B ) = ( ( { a | E. p e. L E. q e. M a = ( ( A x.s B ) -s ( ( A -s p ) x.s ( B -s q ) ) ) } u. { b | E. r e. R E. s e. S b = ( ( A x.s B ) -s ( ( r -s A ) x.s ( s -s B ) ) ) } ) |s ( { c | E. t e. L E. u e. S c = ( ( A x.s B ) +s ( ( A -s t ) x.s ( u -s B ) ) ) } u. { d | E. v e. R E. w e. M d = ( ( A x.s B ) +s ( ( v -s A ) x.s ( B -s w ) ) ) } ) ) ) |