let M1, M2 be Matrix of COMPLEX; :: thesis: ( len M1 = len M & width M1 = width M & ( for i, j being Nat st [i,j] in Indices M holds
M1 * (i,j) = (M * (i,j)) *' ) & len M2 = len M & width M2 = width M & ( for i, j being Nat st [i,j] in Indices M holds
M2 * (i,j) = (M * (i,j)) *' ) implies M1 = M2 )
assume that
A6: len M1 = len M and
A7: width M1 = width M and
A8: for i, j being Nat st [i,j] in Indices M holds
M1 * (i,j) = (M * (i,j)) *' and
A9: len M2 = len M and
A10: width M2 = width M and
A11: for i, j being Nat st [i,j] in Indices M holds
M2 * (i,j) = (M * (i,j)) *' ; :: thesis: M1 = M2

now :: thesis: for i, j being Nat st [i,j] in Indices M1 holds
M1 * (i,j) = M2 * (i,j)

let i, j be Nat; :: thesis: ( [i,j] in Indices M1 implies M1 * (i,j) = M2 * (i,j) )
assume A12: [i,j] in Indices M1 ; :: thesis: M1 * (i,j) = M2 * (i,j)
A13: dom M1 = dom M by A6, FINSEQ_3:29;
hence M1 * (i,j) = (M * (i,j)) *' by A7, A8, A12
.= M2 * (i,j) by A7, A11, A12, A13 ;
:: thesis: verum

end;

hence M1 = M2 by A6, A7, A9, A10, MATRIX_0:21; :: thesis: verum