countable family
21Axiom of choice — This article is about the mathematical concept. For the band named after it, see Axiom of Choice (band). In mathematics, the axiom of choice, or AC, is an axiom of set theory stating that for every family of nonempty sets there exists a family of …
22Locally convex topological vector space — In functional analysis and related areas of mathematics, locally convex topological vector spaces or locally convex spaces are examples of topological vector spaces (TVS) which generalize normed spaces. They can be defined as topological vector… …
23Fréchet space — This article is about Fréchet spaces in functional analysis. For Fréchet spaces in general topology, see T1 space. For the type of sequential space, see Fréchet Urysohn space. In functional analysis and related areas of mathematics, Fréchet… …
24Uniform space — In the mathematical field of topology, a uniform space is a set with a uniform structure. Uniform spaces are topological spaces with additional structure which is used to define uniform properties such as completeness, uniform continuity and… …
25Locally finite collection — In the mathematical field of topology, local finiteness is a property of collections of subsets of a topological space. It is fundamental in the study of paracompactness and topological dimension. A collection of subsets of a topological space X… …
26Topological vector space — In mathematics, a topological vector space is one of the basic structures investigated in functional analysis. As the name suggests the space blends a topological structure (a uniform structure to be precise) with the algebraic concept of a… …
27Rasiowa-Sikorski lemma — In axiomatic set theory, the Rasiowa Sikorski lemma is one of the most fundamental facts used in the technique of forcing. In the area of forcing, a subset D of a forcing notion ( P , ≤) is called dense in P if for any p ∈ P there is d ∈ D with d …
28Carathéodory's extension theorem — See also Carathéodory s theorem for other meanings. In measure theory, Carathéodory s extension theorem proves that for a given set Ω, you can always extend a sigma; finite measure defined on R to the sigma; algebra generated by R , where R is a… …
29Set of uniqueness — M set redirects here. For the CityRail train, see CityRail M set. In mathematics, a set of uniqueness is a concept relevant to trigonometric expansions which are not necessarily Fourier series. Their study is a relatively pure branch of harmonic… …
30FK-space — In functional analysis and related areas of mathematics a FK space or Fréchet coordinate space is a sequence space equipped with a topological structure such that it becomes a Fréchet space. FK spaces with a normable topology are called BK spaces …
