In geometric topology, a branch of mathematics, the Bing shrinking criterion, introduced by Bing (1952), is a method for showing that a quotient of a space is homeomorphic to the space.
References Bing, R. H. (1952), "A homeomorphism between the 3-sphere and the sum of two solid horned spheres", Annals of Mathematics, Second Series, 56: 354–362, doi:10.2307/1969804, ISSN 0003-486X, JSTOR 1969804, MR 0049549