Let me add RSA, Elliptic curves, Runge–Kutta, Finite element analysis, and Hamming codes to the list.
I would still consider CSP, Petri Nets, and Pi-Calculus mathematical enough to be wrapped under a mathematics price if they're influential enough. The first true computer scientists were mathematicians, and I still feel that much of the theoretical work in the field is closer to "mathematics useful for computers" than its separate field.
In the spirit of the nobel price, "mathematics with the greatest humanitarian impact" leaves plenty of room for the inclusion of influential pieces from theoretical computer science, especially as those prices within mathematics that do exist already include loads of mathematics that require computers to prove or solve.