injective function
121Stone–Čech compactification — In the mathematical discipline of general topology, Stone–Čech compactification is a technique for constructing a universal map from a topological space X to a compact Hausdorff space beta; X . The Stone–Čech compactification beta; X of a… …
122Invariance of domain — is a theorem in topology about homeomorphic subsets of Euclidean space R n . It states: :If U is an open subset of R n and f : U rarr; R n is an injective continuous map, then V = f ( U ) is open and f is a homeomorphism between U and V .The… …
123Gelfand representation — In mathematics, the Gelfand representation in functional analysis (named after I. M. Gelfand) has two related meanings:* a way of representing commutative Banach algebras as algebras of continuous functions; * the fact that for commutative C*… …
124Category of metric spaces — The category Met, first considered by Isbell (1964), has metric spaces as objects and metric maps or short maps as morphisms. This is a category because the composition of two metric maps is again metric.The monomorphisms in Met are the injective …
125Duality (mathematics) — In mathematics, a duality, generally speaking, translates concepts, theorems or mathematical structures into other concepts, theorems or structures, in a one to one fashion, often (but not always) by means of an involution operation: if the dual… …
126Semigroup action — In algebra and theoretical computer science, an action or act of a semigroup on a set is a rule which associates to each element of the semigroup a transformation of the set in such a way that the product of two elements of the semigroup (using… …
127Composition of relations — In mathematics, the composition of binary relations is a concept of forming a new relation S ∘ R from two given relations R and S, having as its most well known special case the composition of functions. Contents 1 Definition 2 Properties 3 J …
128Arrangement (Mathématiques) — Arrangement Pour les articles homonymes, voir Arrangement (homonymie). La notion d arrangement est utilisée en probabilités, et notamment pour les dénombrements en analyse combinatoire. En mathématiques, lorsque nous choisissons k objets parmi n… …
