ABSTRACT
This chapter explores some general remarks about sets. If S is a set, then a binary operation on S is a way to “combine” two elements of S, obtaining another element of S. Although we are concentrating here on square matrices, we should mention that non-square matrices can be multiplied under the right conditions. Turning back to matrices then, we wish to describe identity elements and inverse elements for the two binary operations addition and multiplication on the set of n × n matrices. The matter of multiplicative inverses of square matrices is more complicated.
