Is anyone here applying abstract algebra to technology projects which might interest us HN readers? I studied it as an undergraduate; when I think about applic

Is anyone here applying abstract algebra to technology projects which might interest us HN readers? I studied it as an undergraduate; when I think about applications I've found in technology work and computer science, the following spring to mind: * Linear algebra -- obviously very useful, although not everyone would consider it abstract enough to lump under abstract algebra. * The structural side (category theory, universal algebra etc) very useful for grokking theoretical computer science * Lattices, order theory, boolean algebras etc -- also very useful for computer science, but perhaps tending a bit away from algebra and towards logic. I'm not sure I've really wielded in anger any non-trivial theorems from the theory of groups and rings though. Maybe a little bit of basic group theory. But perhaps I've lead a boring life. Interested to hear what people are doing with it in the tech / comp sci field :) (Crypto, I guess, is one important area. And the 'patch algebra' of the darcs VCS was another interesting application I spotted)