This will be old news to anyone who does algebraic topology, but oddly enough I can't seem to find it all written in one place anywhere, and in particular I can't find the bit about $latex {\mathsf{hPairTop}}&fg=000000$ at all. In algebraic topology you (for example) associate every topological space $latex {X}&fg=000000$ with a group, like… Continue reading Algebraic Topology Functors