Robert - I find that Wikipedia and the nLab are pretty good about pointing out the links between concepts. So that's where I often start. But talking to people is even better, which is why I "waste my time" blogging so much.

By the way: a corelation is not exactly the same as a partition: a corelation \\(f : X \to Y\\) is the same as a partition of \\(X + Y\\) (that is, the disjoint union of \\(X\\) and \\(Y\\)). That's different enough to deserve a different name.

On the other hand, partitions of a set \\(X\\) are in one-to-one correspondence with equivalence relations on \\(X\\)... so "partition" and "equivalence relation" are really just two different ways of thinking about the same thing. It's probably a useful difference, but it may fool some people into not noticing the unity of the concepts.

By the way: a corelation is not exactly the same as a partition: a corelation \\(f : X \to Y\\) is the same as a partition of \\(X + Y\\) (that is, the disjoint union of \\(X\\) and \\(Y\\)). That's different enough to deserve a different name.

On the other hand, partitions of a set \\(X\\) are in one-to-one correspondence with equivalence relations on \\(X\\)... so "partition" and "equivalence relation" are really just two different ways of thinking about the same thing. It's probably a useful difference, but it may fool some people into not noticing the unity of the concepts.