> Mathematics is the mathematics of abstraction. > Category theory is the mathematics of composition. I don't know why you're being downvoted (tone?) but you'

> Mathematics is the mathematics of abstraction. > Category theory is the mathematics of composition. I don't know why you're being downvoted (tone?) but you're right. Categories formalize exactly and only the notion of composition; its power is that this notion appears everywhere when you know what to look for. Most mathematical abstractions have composition baked in at one level or another, so I think the author should be pardoned for their phrasing; but I find yours more enlightening.