> I sometimes wonder if it's differentiation is P and integration is NP (for the restricted case of functions where the primitives are "nice") It's something p

> I sometimes wonder if it's differentiation is P and integration is NP (for the restricted case of functions where the primitives are "nice") It's something pretty close to this. Almost all mathematical expressions can't be integrated (up to the reader to formalise the definitions here). That is not quite the same claim as saying that the best method for solving an arbitrary integral is trial and error by systematically differentiating other expressions until you find the antiderivative.