Min-max theorem

Variational characterization of eigenvalues of compact Hermitian operators on Hilbert spaces

In linear algebra and functional analysis, the min-max theorem, or variational theorem, or Courant–Fischer–Weyl min-max principle, is a result that gives a variational characterization of eigenvalues of compact Hermitian operators on Hilbert spaces. It can be viewed as the starting point of many results of similar nature.

This keyword could refer to multiple things. Here are some suggestions: