Similar to ファトゥの補題

Five lemma

Arzelà–Ascoli theorem

Apollonius point

Itô's lemma

Schwarz lemma

Apollonius's theorem

Euler's formula

Gauss's lemma (number theory)

Carathéodory's theorem (convex hull)

Kőnig's lemma

Kempner series

Cauchy's mean value theorem

Schiffler point

Sylvester–Gallai theorem

Stewart's theorem

Diagonal lemma

Thales's theorem

Ceva's theorem

Hardy–Littlewood inequality

Bézout's identity

Calculus on Manifolds (book)

P-adic analysis

Wirtinger derivatives

Volterra integral equation

Gaussian integral

Grönwall's inequality