set K = F_Complex ;
let V, W be VectSp of F_Complex ; :: thesis: for f being sesquilinear-Form of V,W holds
( Q*Form f = RQ*Form (LQForm f) & Q*Form f = LQForm (RQ*Form f) )

let f be sesquilinear-Form of V,W; :: thesis: ( Q*Form f = RQ*Form (LQForm f) & Q*Form f = LQForm (RQ*Form f) )
set L = LKer f;
set vq = VectQuot V,(LKer f);
set R = RKer (f *' );
set wq = VectQuot W,(RKer (f *' ));
set RL = RKer ((LQForm f) *' );
set wqr = VectQuot W,(RKer ((LQForm f) *' ));
set LR = LKer (RQ*Form f);
set vql = VectQuot V,(LKer (RQ*Form f));
A1: dom (Q*Form f) = [:the carrier of (VectQuot V,(LKer f)),the carrier of (VectQuot W,(RKer (f *' ))):] by FUNCT_2:def 1;
A2: now
A3: RKer (f *' ) = RKer ((LQForm f) *' ) by Th64;
let x be set ; :: thesis: ( x in dom (Q*Form f) implies (Q*Form f) . x = (RQ*Form (LQForm f)) . x )
assume x in dom (Q*Form f) ; :: thesis: (Q*Form f) . x = (RQ*Form (LQForm f)) . x
then consider A, B being set such that
A4: A in the carrier of (VectQuot V,(LKer f)) and
A5: B in the carrier of (VectQuot W,(RKer (f *' ))) and
A6: x = [A,B] by ZFMISC_1:def 2;
reconsider A = A as Vector of (VectQuot V,(LKer f)) by A4;
consider v being Vector of V such that
A7: A = v + (LKer f) by VECTSP10:23;
reconsider B = B as Vector of (VectQuot W,(RKer (f *' ))) by A5;
consider w being Vector of W such that
A8: B = w + (RKer (f *' )) by VECTSP10:23;
thus (Q*Form f) . x = (Q*Form f) . A,B by A6
.= f . v,w by A7, A8, Def12
.= (LQForm f) . A,w by A7, BILINEAR:def 21
.= (RQ*Form (LQForm f)) . A,B by A8, A3, Th62
.= (RQ*Form (LQForm f)) . x by A6 ; :: thesis: verum
end;
( dom (RQ*Form (LQForm f)) = [:the carrier of (VectQuot V,(LKer f)),the carrier of (VectQuot W,(RKer ((LQForm f) *' ))):] & the carrier of (VectQuot W,(RKer ((LQForm f) *' ))) = the carrier of (VectQuot W,(RKer (f *' ))) ) by Th64, FUNCT_2:def 1;
hence Q*Form f = RQ*Form (LQForm f) by A1, A2, FUNCT_1:9; :: thesis: Q*Form f = LQForm (RQ*Form f)
A9: now
A10: LKer f = LKer (RQ*Form f) by Th65;
let x be set ; :: thesis: ( x in dom (Q*Form f) implies (Q*Form f) . x = (LQForm (RQ*Form f)) . x )
assume x in dom (Q*Form f) ; :: thesis: (Q*Form f) . x = (LQForm (RQ*Form f)) . x
then consider A, B being set such that
A11: A in the carrier of (VectQuot V,(LKer f)) and
A12: B in the carrier of (VectQuot W,(RKer (f *' ))) and
A13: x = [A,B] by ZFMISC_1:def 2;
reconsider A = A as Vector of (VectQuot V,(LKer f)) by A11;
consider v being Vector of V such that
A14: A = v + (LKer f) by VECTSP10:23;
reconsider B = B as Vector of (VectQuot W,(RKer (f *' ))) by A12;
consider w being Vector of W such that
A15: B = w + (RKer (f *' )) by VECTSP10:23;
thus (Q*Form f) . x = (Q*Form f) . A,B by A13
.= f . v,w by A14, A15, Def12
.= (RQ*Form f) . v,B by A15, Th62
.= (LQForm (RQ*Form f)) . A,B by A14, A10, BILINEAR:def 21
.= (LQForm (RQ*Form f)) . x by A13 ; :: thesis: verum
end;
( dom (LQForm (RQ*Form f)) = [:the carrier of (VectQuot V,(LKer (RQ*Form f))),the carrier of (VectQuot W,(RKer (f *' ))):] & the carrier of (VectQuot V,(LKer (RQ*Form f))) = the carrier of (VectQuot V,(LKer f)) ) by Th65, FUNCT_2:def 1;
hence Q*Form f = LQForm (RQ*Form f) by A1, A9, FUNCT_1:9; :: thesis: verum