Metamath 與 PiBase: Topology 使用情況與統計

π-Base Topology is a community database of topological counterexamples. The database has: - Topological Spaces - Topological Theorems. - Topological Properties. - References (Books, Articles, Forums). Information inside the app: - Space, Theorem and Property descriptions. - Properties that are (and aren´t) satisfied by a given space. - Converses of theorems for which a given space is a counterexample. - Given a property, which spaces satisfy and don´t satisfy it. - Counterexamples for the converse of a given theorem. If the converse is True, a proof or reference is given. - Spaces that satisfy a given logical formula formed with properties (search by formula). - References.