Eisenbud–Levine–Khimshiashvili signature formula

In mathematics, and especially differential topology and singularity theory, the Eisenbud–Levine–Khimshiashvili signature formula gives a way of computing the Poincaré–Hopf index of a real, analytic vector field at an algebraically isolated singularity. It is named after David Eisenbud, Harold I. Levine, and George Khimshiashvili.

Source: Wikipedia — Eisenbud–Levine–Khimshiashvili signature formula (CC BY-SA 4.0)