(topology, formally) An ordered pair (X, τ), where X is a set and τ, called the topology, is a collection of subsets of X which satisfies certain axioms and whose elements are called the open sets (or alternatively, for a different set of axioms, the closed sets);

a material which conducts electrons only along its edges and surfaces, but does not conduct in its interior

plural of topological insulator

plural of link topology

plural of Grothendieck topology

(category theory) A structure on a category which makes the category's objects act like the open sets of a topological space.

(topology) A group which is also a topological space and whose group operations are continuous functions.

plural of topological group

(topology) A topology on a set consisting of all subsets of that set.

plural of discrete topology