try to look at it as a kind of format were you are storing equations (by the moment) You process the operations between such equations -sum, inner, outer- by "

try to look at it as a kind of format were you are storing equations (by the moment) You process the operations between such equations -sum, inner, outer- by "unpacking" them into Matrix equations format (populating the Matrix with the vector values), doing the operations, and returning back to the vector format. So in essence you are working with Matrix equations, but with a more compact format as vector. For being able to work with such equations' compact format, its needed to follow some rules restricted to the purpose, case contrary, as in reality they are vectors per se, the geometries could mix dimensions were the equations' proprieties are different.