As much as I respect djb, the title is a huge misnomer. If you're a mathematician you want analysis and topology. You want definitions of continuity and differe

As much as I respect djb, the title is a huge misnomer. If you're a mathematician you want analysis and topology. You want definitions of continuity and differentiability that generalize nicely to arbitrary dimension, to manifolds, to Lie groups, to whatever. You want to marvel at the connections between certain special integrals and infinite sums, and you want to see the full construction of the real numbers for its own sake. You want a list of equivalent definitions of differentiability so you can get a better intuition and use whichever one is the nicest for what you're trying to do. In a very strong sense, writing a document that "focuses purely on calculus" is antithetical to mathematics.