Morse theory

Etymology
Based on the work of.

Noun

 * 1)  The study of differentiable functions, where the domain of each is a manifold and the codomain is the real line.
 * 2) * March 14, 2018, Roger Penrose writing in The Guardian, 'Mind over matter': Stephen Hawking – obituary
 * the spaces that are used in Einstein’s theory are really pseudo-Riemannian and the relevant Morse theory differs in subtle but important ways.