mrfox321·3 lata temu·discussYeah matrices are more abstract. I guess I am just pointing out that your concrete example of non-commutative rings (matrices of matrices) still needs a proof to demonstrate bijection between 4N x 4N (scalar) and 4 x 4 (N x N(scalar)).Block MM demonstrates the equivalence.
mrfox321·3 lata temu·discussRe [1]: it's fairly concrete to simply say that matrix multiplication can be performed block-wise.