Matrix product of matrices A and B is the third matrix C
If A is mxn, B is nxp, then C is mxp.
Subject to the distributive property of matrix multiplication: A (B + C) = AB + AC
Associative: A (BC) = (AB) C
Not commutative
Transposed matrix product:
Matrix the I n- : all the elements along the diagonal is 1, while the other positions are zero elements
The inverse matrix A: A -1
Matrix and the inverse matrix satisfies: A -1 A = the I n-