let M1, M2 be Matrix of COMPLEX ; :: thesis: ( len M1 = len M2 & width M1 = width M2 implies (M1 - M2) *' = (M1 *' ) - (M2 *' ) )
assume A1: ( len M1 = len M2 & width M1 = width M2 ) ; :: thesis: (M1 - M2) *' = (M1 *' ) - (M2 *' )
A2: len ((M1 - M2) *' ) = len (M1 - M2) by Def1;
A3: len (M1 *' ) = len M1 by Def1;
A4: len (M2 *' ) = len M2 by Def1;
A5: width (M1 *' ) = width M1 by Def1;
A6: width (M2 *' ) = width M2 by Def1;
A7: len (M1 - M2) = len M1 by Th13;
A8: len ((M1 *' ) - (M2 *' )) = len (M1 *' ) by Th13;
A9: width ((M1 - M2) *' ) = width (M1 - M2) by Def1;
A10: width (M1 - M2) = width M1 by Th13;
A11: width ((M1 *' ) - (M2 *' )) = width (M1 *' ) by Th13;
A12: width (M1 *' ) = width M1 by Def1;
now
let i, j be Nat; :: thesis: ( [i,j] in Indices ((M1 - M2) *' ) implies ((M1 - M2) *' ) * i,j = ((M1 *' ) - (M2 *' )) * i,j )
assume [i,j] in Indices ((M1 - M2) *' ) ; :: thesis: ((M1 - M2) *' ) * i,j = ((M1 *' ) - (M2 *' )) * i,j
then A13: ( 1 <= i & i <= len (M1 - M2) & 1 <= j & j <= width (M1 - M2) ) by A2, A9, Th1;
then A14: [i,j] in Indices (M1 - M2) by Th1;
A15: [i,j] in Indices M1 by A7, A10, A13, Th1;
( 1 <= i & i <= len (M1 *' ) & 1 <= j & j <= width (M1 *' ) ) by A7, A10, A13, Def1;
then A16: [i,j] in Indices (M1 *' ) by Th1;
A17: [i,j] in Indices M2 by A1, A7, A10, A13, Th1;
((M1 - M2) *' ) * i,j = ((M1 - M2) * i,j) *' by A14, Def1;
hence ((M1 - M2) *' ) * i,j = ((M1 * i,j) - (M2 * i,j)) *' by A1, A15, Th14
.= ((M1 * i,j) *' ) - ((M2 * i,j) *' ) by COMPLEX1:120
.= ((M1 *' ) * i,j) - ((M2 * i,j) *' ) by A15, Def1
.= ((M1 *' ) * i,j) - ((M2 *' ) * i,j) by A17, Def1
.= ((M1 *' ) - (M2 *' )) * i,j by A1, A3, A4, A5, A6, A16, Th14 ;
:: thesis: verum
end;
hence (M1 - M2) *' = (M1 *' ) - (M2 *' ) by A2, A3, A7, A8, A9, A10, A11, A12, MATRIX_1:21; :: thesis: verum