Topological Space
Handbook of analysis and its foundations 1997.
Topological space. Log in definition of topological space. Some things to note. A set x consisting of elements of an arbitrary nature called points of the given space and a topological structure or topology on this set x cf.
A topological space is a space studied in topology the mathematics of the structure of shapes roughly it is a set of things called points along with a way to know which things are close together. A subspace a of a space x with topology tau is quasi h closed relative to x if each tau open family which covers a. A space x is quasi h closed if every open cover has a finite proximate subcover i e it has a finite subfamily whose closures form a cover of the space.
A topological space also called an abstract topological space is a set together with a collection of open subsets that satisfies the four conditions. Topological space in mathematics generalization of euclidean spaces in which the idea of closeness or limits is described in terms of relationships between sets rather than in terms of distance. The empty set and x itself belong to τ.
A topological space is zero dimensional if it has a base consisting of clopen sets i e if every open set can be expressed as a union of clopen sets. It is immaterial whether this is an open or closed topology one transfers into the other by replacing the sets constituting the given topology by their complements. Any arbitrary finite or infinite union of members of τ still belongs to τ.
A topological space is a set endowed with a structure called a topology which allows defining continuous deformation of subspaces and more generally all kinds of continuity. The empty set is in. A totality of two elements.
The intersection of any finite number of members of τ still belongs to τ. More precisely a topological space has a certain kind of set called open sets open sets are important because they allow one to talk about points near another point called a neighbourhood of. It does not strictly make sense to merely say that a set is open.