Metamath Proof Explorer


Theorem cramerlem2

Description: Lemma 2 for cramer . (Contributed by AV, 21-Feb-2019) (Revised by AV, 1-Mar-2019)

Ref Expression
Hypotheses cramer.a
|- A = ( N Mat R )
cramer.b
|- B = ( Base ` A )
cramer.v
|- V = ( ( Base ` R ) ^m N )
cramer.d
|- D = ( N maDet R )
cramer.x
|- .x. = ( R maVecMul <. N , N >. )
cramer.q
|- ./ = ( /r ` R )
Assertion cramerlem2
|- ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) -> A. z e. V ( ( X .x. z ) = Y -> z = ( i e. N |-> ( ( D ` ( ( X ( N matRepV R ) Y ) ` i ) ) ./ ( D ` X ) ) ) ) )

Proof

Step Hyp Ref Expression
1 cramer.a
 |-  A = ( N Mat R )
2 cramer.b
 |-  B = ( Base ` A )
3 cramer.v
 |-  V = ( ( Base ` R ) ^m N )
4 cramer.d
 |-  D = ( N maDet R )
5 cramer.x
 |-  .x. = ( R maVecMul <. N , N >. )
6 cramer.q
 |-  ./ = ( /r ` R )
7 simpll1
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> R e. CRing )
8 simpll2
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> ( X e. B /\ Y e. V ) )
9 simpll3
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> ( D ` X ) e. ( Unit ` R ) )
10 simplr
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> z e. V )
11 simpr
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> ( X .x. z ) = Y )
12 1 2 3 4 5 6 cramerlem1
 |-  ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( ( D ` X ) e. ( Unit ` R ) /\ z e. V /\ ( X .x. z ) = Y ) ) -> z = ( i e. N |-> ( ( D ` ( ( X ( N matRepV R ) Y ) ` i ) ) ./ ( D ` X ) ) ) )
13 7 8 9 10 11 12 syl113anc
 |-  ( ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) /\ ( X .x. z ) = Y ) -> z = ( i e. N |-> ( ( D ` ( ( X ( N matRepV R ) Y ) ` i ) ) ./ ( D ` X ) ) ) )
14 13 ex
 |-  ( ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) /\ z e. V ) -> ( ( X .x. z ) = Y -> z = ( i e. N |-> ( ( D ` ( ( X ( N matRepV R ) Y ) ` i ) ) ./ ( D ` X ) ) ) ) )
15 14 ralrimiva
 |-  ( ( R e. CRing /\ ( X e. B /\ Y e. V ) /\ ( D ` X ) e. ( Unit ` R ) ) -> A. z e. V ( ( X .x. z ) = Y -> z = ( i e. N |-> ( ( D ` ( ( X ( N matRepV R ) Y ) ` i ) ) ./ ( D ` X ) ) ) ) )