infinite subgroup
61Fundamental theorem of Galois theory — In mathematics, the fundamental theorem of Galois theory is a result that describes the structure of certain types of field extensions.In its most basic form, the theorem asserts that given a field extension E / F which is finite and Galois,… …
62Von Neumann algebra — In mathematics, a von Neumann algebra or W* algebra is a * algebra of bounded operators on a Hilbert space that is closed in the weak operator topology and contains the identity operator. They were originally introduced by John von Neumann,… …
63System of imprimitivity — The concept of system of imprimitivity is used in mathematics, particularly in algebra and analysis, both within the context of the theory of group representations. It was used by George Mackey as the basis for his theory of induced unitary… …
64Symmetric space — In differential geometry, representation theory and harmonic analysis, a symmetric space is a smooth manifold whose group of symmetries contains an inversion symmetry about every point. There are two ways to make this precise. In Riemannian… …
65Banach–Tarski paradox — The Banach–Tarski paradox is a theorem in set theoretic geometry which states that a solid ball in 3 dimensional space can be split into several non overlapping pieces, which can then be put back together in a different way to yield two identical …
66Dihedral group — This snowflake has the dihedral symmetry of a regular hexagon. In mathematics, a dihedral group is the group of symmetries of a regular polygon, including both rotations and reflections.[1] Dihedr …
67Symmetry — For other uses, see Symmetry (disambiguation) …
68Order (group theory) — This article is about order in group theory. For order in other branches of mathematics, see Order (mathematics). For order in other disciplines, see Order. In group theory, a branch of mathematics, the term order is used in two closely related… …
69Crossed product — In mathematics, and more specifically in the theory of von Neumann algebras, a crossed product is a basic method of constructing a new von Neumann algebra from a von Neumann algebra acted on by a group. It is related to the semidirect product… …
70Fitting's theorem — is a mathematical theorem proved by Hans Fitting. It can be stated as follows::If M and N are nilpotent normal subgroups of a group G , then their product MN is also a nilpotent normal subgroup of G ; if, moreover, M is nilpotent of class m and N …
