infinite subgroup
51Ping-pong lemma — In mathematics, the ping pong lemma, or table tennis lemma, is any of several mathematical statements which ensure that several elements in a group acting on a set freely generate a free subgroup of that group.HistoryThe ping pong argument goes… …
52Hawaiian earring — In mathematics, the Hawaiian earring H is the topological space defined by the union of circles in the Euclidean plane R^2 with center (1/n,0) and radius 1/n for n=1,2,3,.... H is homeomorphic to the one point compactification of a countably… …
53Discrete group — Concepts in group theory category of groups subgroups, normal subgroups group homomorphisms, kernel, image, quotient direct product, direct sum semidirect product, wreath product …
54Geometric group theory — is an area in mathematics devoted to the study of finitely generated groups via exploring the connections between algebraic properties of such groups and topological and geometric properties of spaces on which these groups act (that is, when the… …
55Automorphisms of the symmetric and alternating groups — In group theory, a branch of mathematics, the automorphisms and outer automorphisms of the symmetric groups and alternating groups are both standard examples of these automorphisms, and objects of study in their own right, particularly the… …
56Local property — In mathematics, a phenomenon is sometimes said to occur locally if, roughly speaking, it occurs on sufficiently small or arbitrarily small neighborhoods of points. Contents 1 Properties of a single space 1.1 Examples 2 Properties of a pair of… …
57Euclidean plane isometry — In geometry, a Euclidean plane isometry is an isometry of the Euclidean plane, or more informally, a way of transforming the plane that preserves geometrical properties such as length. There are four types: translations, rotations, reflections,… …
58Coset — In mathematics, if G is a group, and H is a subgroup of G, and g is an element of G, then gH = {gh : h an element of H } is a left coset of H in G, and Hg = {hg : h an element of H } is a right coset of H in G. Only when H is normal… …
59Generating set of a group — In abstract algebra, a generating set of a group is a subset that is not contained in any proper subgroup of the group. Equivalently, a generating set of a group is a subset such that every element of the group can be expressed as the combination …
60List of finite simple groups — In mathematics, the classification of finite simple groups states thatevery finite simple group is cyclic, or alternating, or in one of 16 families of groups of Lie type (including the Tits group, which strictly speaking is not of Lie type),or… …
