1 isn't a matrix. Integers/floating point numbers are in many languages treated differently than other types for reasons of performance and memory management etc. Ruby isn't different in this respect (IIRC they call it immediate objects). A matrix is a "normal" object in ruby.
BTW the ruby equivalent for the above convention would be (maybe inspired by scheme?)
a.inverse!() -> mutate a
a.inverse() -> return the inverse
I am a python user, but I _really_ like that .inverse!() notation indicating that the object itself is being mutated. It's concise and consistent. Sometimes punctuation in names is exactly what you need. Same with ? for predicates. I'll take even? over evenp any day of the week.
A Fixnum could be interpreted as a 1x1 matrix. For some recursive solutions, it would probably be nice of MatrixMath.inverse accepted it as such, as well as [[1]].
This confuses me, because python strings use str.lower() to return a lowercase copy of str, leaving str unchanged. I prefer the Ruby idiom of naming the mutating versions with a !.
