Švarc–Milnor lemma
LEMMA IN GEOMETRIC GROUP THEORY, GIVING SUFFICIENT CONDITIONS FOR WHEN A GROUP EQUIPPED WITH AN ISOMETRIC ACTION ON A METRIC SPACE IS QUASI-ISOMETRIC TO THE METRIC SPACE
Švarc-Milnor lemma; Schwarz-Milnor lemma
In the mathematical subject of geometric group theory, the Švarc–Milnor lemma (sometimes also called Milnor–Švarc lemma, with both variants also sometimes spelling Švarc as Schwarz) is a statement which says that a group G, equipped with a "nice" discrete isometric action on a metric space X, is quasi-isometric to X.