This POV comes from Kuhn;
I'm applying it to math.

Modern formulations of mathematical theories are not their orginial
formulations: they are the theory \emph{as refined} by succeeding generations.

Still recognizably the same theory, but in a more polished
and better-understood form.

Some examples:
Calculus
Similarly, calculus today is not Newton and Leibniz's;
it is as refined, especially by Weierstra\ss.

Riemannian geometry

Riemannian geometry today is not the theory as developed by Riemann:
it is the theory as refined

(Kuhn's example)
Newtonian physics is not Newton's physics:
it's that theory as refined, particular in the Lagrangian and Hamiltonian
formulations.

