| Step | Hyp | Ref | Expression | 
						
							| 1 |  | evlslem4.b |  |-  B = ( Base ` R ) | 
						
							| 2 |  | evlslem4.z |  |-  .0. = ( 0g ` R ) | 
						
							| 3 |  | evlslem4.t |  |-  .x. = ( .r ` R ) | 
						
							| 4 |  | evlslem4.r |  |-  ( ph -> R e. Ring ) | 
						
							| 5 |  | evlslem4.x |  |-  ( ( ph /\ x e. I ) -> X e. B ) | 
						
							| 6 |  | evlslem4.y |  |-  ( ( ph /\ y e. J ) -> Y e. B ) | 
						
							| 7 |  | evlslem4.i |  |-  ( ph -> I e. V ) | 
						
							| 8 |  | evlslem4.j |  |-  ( ph -> J e. W ) | 
						
							| 9 |  | simp2 |  |-  ( ( ph /\ x e. I /\ y e. J ) -> x e. I ) | 
						
							| 10 | 5 | 3adant3 |  |-  ( ( ph /\ x e. I /\ y e. J ) -> X e. B ) | 
						
							| 11 |  | eqid |  |-  ( x e. I |-> X ) = ( x e. I |-> X ) | 
						
							| 12 | 11 | fvmpt2 |  |-  ( ( x e. I /\ X e. B ) -> ( ( x e. I |-> X ) ` x ) = X ) | 
						
							| 13 | 9 10 12 | syl2anc |  |-  ( ( ph /\ x e. I /\ y e. J ) -> ( ( x e. I |-> X ) ` x ) = X ) | 
						
							| 14 |  | simp3 |  |-  ( ( ph /\ x e. I /\ y e. J ) -> y e. J ) | 
						
							| 15 |  | eqid |  |-  ( y e. J |-> Y ) = ( y e. J |-> Y ) | 
						
							| 16 | 15 | fvmpt2 |  |-  ( ( y e. J /\ Y e. B ) -> ( ( y e. J |-> Y ) ` y ) = Y ) | 
						
							| 17 | 14 6 16 | 3imp3i2an |  |-  ( ( ph /\ x e. I /\ y e. J ) -> ( ( y e. J |-> Y ) ` y ) = Y ) | 
						
							| 18 | 13 17 | oveq12d |  |-  ( ( ph /\ x e. I /\ y e. J ) -> ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) = ( X .x. Y ) ) | 
						
							| 19 | 18 | mpoeq3dva |  |-  ( ph -> ( x e. I , y e. J |-> ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) ) = ( x e. I , y e. J |-> ( X .x. Y ) ) ) | 
						
							| 20 |  | nfcv |  |-  F/_ i ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) | 
						
							| 21 |  | nfcv |  |-  F/_ j ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) | 
						
							| 22 |  | nffvmpt1 |  |-  F/_ x ( ( x e. I |-> X ) ` i ) | 
						
							| 23 |  | nfcv |  |-  F/_ x .x. | 
						
							| 24 |  | nfcv |  |-  F/_ x ( ( y e. J |-> Y ) ` j ) | 
						
							| 25 | 22 23 24 | nfov |  |-  F/_ x ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) | 
						
							| 26 |  | nfcv |  |-  F/_ y ( ( x e. I |-> X ) ` i ) | 
						
							| 27 |  | nfcv |  |-  F/_ y .x. | 
						
							| 28 |  | nffvmpt1 |  |-  F/_ y ( ( y e. J |-> Y ) ` j ) | 
						
							| 29 | 26 27 28 | nfov |  |-  F/_ y ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) | 
						
							| 30 |  | fveq2 |  |-  ( x = i -> ( ( x e. I |-> X ) ` x ) = ( ( x e. I |-> X ) ` i ) ) | 
						
							| 31 |  | fveq2 |  |-  ( y = j -> ( ( y e. J |-> Y ) ` y ) = ( ( y e. J |-> Y ) ` j ) ) | 
						
							| 32 | 30 31 | oveqan12d |  |-  ( ( x = i /\ y = j ) -> ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) = ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) ) | 
						
							| 33 | 20 21 25 29 32 | cbvmpo |  |-  ( x e. I , y e. J |-> ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) ) = ( i e. I , j e. J |-> ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) ) | 
						
							| 34 |  | vex |  |-  i e. _V | 
						
							| 35 |  | vex |  |-  j e. _V | 
						
							| 36 | 34 35 | eqop2 |  |-  ( z = <. i , j >. <-> ( z e. ( _V X. _V ) /\ ( ( 1st ` z ) = i /\ ( 2nd ` z ) = j ) ) ) | 
						
							| 37 |  | fveq2 |  |-  ( ( 1st ` z ) = i -> ( ( x e. I |-> X ) ` ( 1st ` z ) ) = ( ( x e. I |-> X ) ` i ) ) | 
						
							| 38 |  | fveq2 |  |-  ( ( 2nd ` z ) = j -> ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) = ( ( y e. J |-> Y ) ` j ) ) | 
						
							| 39 | 37 38 | oveqan12d |  |-  ( ( ( 1st ` z ) = i /\ ( 2nd ` z ) = j ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) ) | 
						
							| 40 | 36 39 | simplbiim |  |-  ( z = <. i , j >. -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) ) | 
						
							| 41 | 40 | mpompt |  |-  ( z e. ( I X. J ) |-> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) = ( i e. I , j e. J |-> ( ( ( x e. I |-> X ) ` i ) .x. ( ( y e. J |-> Y ) ` j ) ) ) | 
						
							| 42 | 33 41 | eqtr4i |  |-  ( x e. I , y e. J |-> ( ( ( x e. I |-> X ) ` x ) .x. ( ( y e. J |-> Y ) ` y ) ) ) = ( z e. ( I X. J ) |-> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) | 
						
							| 43 | 19 42 | eqtr3di |  |-  ( ph -> ( x e. I , y e. J |-> ( X .x. Y ) ) = ( z e. ( I X. J ) |-> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) ) | 
						
							| 44 | 43 | oveq1d |  |-  ( ph -> ( ( x e. I , y e. J |-> ( X .x. Y ) ) supp .0. ) = ( ( z e. ( I X. J ) |-> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) supp .0. ) ) | 
						
							| 45 |  | difxp |  |-  ( ( I X. J ) \ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) = ( ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) u. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) | 
						
							| 46 | 45 | eleq2i |  |-  ( z e. ( ( I X. J ) \ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) <-> z e. ( ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) u. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) ) | 
						
							| 47 |  | elun |  |-  ( z e. ( ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) u. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) <-> ( z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) \/ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) ) | 
						
							| 48 | 46 47 | bitri |  |-  ( z e. ( ( I X. J ) \ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) <-> ( z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) \/ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) ) | 
						
							| 49 |  | xp1st |  |-  ( z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) -> ( 1st ` z ) e. ( I \ ( ( x e. I |-> X ) supp .0. ) ) ) | 
						
							| 50 | 5 | fmpttd |  |-  ( ph -> ( x e. I |-> X ) : I --> B ) | 
						
							| 51 |  | ssidd |  |-  ( ph -> ( ( x e. I |-> X ) supp .0. ) C_ ( ( x e. I |-> X ) supp .0. ) ) | 
						
							| 52 | 2 | fvexi |  |-  .0. e. _V | 
						
							| 53 | 52 | a1i |  |-  ( ph -> .0. e. _V ) | 
						
							| 54 | 50 51 7 53 | suppssr |  |-  ( ( ph /\ ( 1st ` z ) e. ( I \ ( ( x e. I |-> X ) supp .0. ) ) ) -> ( ( x e. I |-> X ) ` ( 1st ` z ) ) = .0. ) | 
						
							| 55 | 49 54 | sylan2 |  |-  ( ( ph /\ z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) ) -> ( ( x e. I |-> X ) ` ( 1st ` z ) ) = .0. ) | 
						
							| 56 | 55 | oveq1d |  |-  ( ( ph /\ z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = ( .0. .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) | 
						
							| 57 | 6 | fmpttd |  |-  ( ph -> ( y e. J |-> Y ) : J --> B ) | 
						
							| 58 |  | xp2nd |  |-  ( z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) -> ( 2nd ` z ) e. J ) | 
						
							| 59 |  | ffvelcdm |  |-  ( ( ( y e. J |-> Y ) : J --> B /\ ( 2nd ` z ) e. J ) -> ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) e. B ) | 
						
							| 60 | 57 58 59 | syl2an |  |-  ( ( ph /\ z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) ) -> ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) e. B ) | 
						
							| 61 | 1 3 2 | ringlz |  |-  ( ( R e. Ring /\ ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) e. B ) -> ( .0. .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 62 | 4 60 61 | syl2an2r |  |-  ( ( ph /\ z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) ) -> ( .0. .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 63 | 56 62 | eqtrd |  |-  ( ( ph /\ z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 64 |  | xp2nd |  |-  ( z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) -> ( 2nd ` z ) e. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) | 
						
							| 65 |  | ssidd |  |-  ( ph -> ( ( y e. J |-> Y ) supp .0. ) C_ ( ( y e. J |-> Y ) supp .0. ) ) | 
						
							| 66 | 57 65 8 53 | suppssr |  |-  ( ( ph /\ ( 2nd ` z ) e. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) -> ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) = .0. ) | 
						
							| 67 | 64 66 | sylan2 |  |-  ( ( ph /\ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) = .0. ) | 
						
							| 68 | 67 | oveq2d |  |-  ( ( ph /\ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. .0. ) ) | 
						
							| 69 |  | xp1st |  |-  ( z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) -> ( 1st ` z ) e. I ) | 
						
							| 70 |  | ffvelcdm |  |-  ( ( ( x e. I |-> X ) : I --> B /\ ( 1st ` z ) e. I ) -> ( ( x e. I |-> X ) ` ( 1st ` z ) ) e. B ) | 
						
							| 71 | 50 69 70 | syl2an |  |-  ( ( ph /\ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( x e. I |-> X ) ` ( 1st ` z ) ) e. B ) | 
						
							| 72 | 1 3 2 | ringrz |  |-  ( ( R e. Ring /\ ( ( x e. I |-> X ) ` ( 1st ` z ) ) e. B ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. .0. ) = .0. ) | 
						
							| 73 | 4 71 72 | syl2an2r |  |-  ( ( ph /\ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. .0. ) = .0. ) | 
						
							| 74 | 68 73 | eqtrd |  |-  ( ( ph /\ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 75 | 63 74 | jaodan |  |-  ( ( ph /\ ( z e. ( ( I \ ( ( x e. I |-> X ) supp .0. ) ) X. J ) \/ z e. ( I X. ( J \ ( ( y e. J |-> Y ) supp .0. ) ) ) ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 76 | 48 75 | sylan2b |  |-  ( ( ph /\ z e. ( ( I X. J ) \ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) ) -> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) = .0. ) | 
						
							| 77 | 7 8 | xpexd |  |-  ( ph -> ( I X. J ) e. _V ) | 
						
							| 78 | 76 77 | suppss2 |  |-  ( ph -> ( ( z e. ( I X. J ) |-> ( ( ( x e. I |-> X ) ` ( 1st ` z ) ) .x. ( ( y e. J |-> Y ) ` ( 2nd ` z ) ) ) ) supp .0. ) C_ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) | 
						
							| 79 | 44 78 | eqsstrd |  |-  ( ph -> ( ( x e. I , y e. J |-> ( X .x. Y ) ) supp .0. ) C_ ( ( ( x e. I |-> X ) supp .0. ) X. ( ( y e. J |-> Y ) supp .0. ) ) ) |