## Mathematics Subject Classification – MSC2010

General reference works (handbooks, dictionaries, bibliographies, etc.) 26

Instructional exposition (textbooks, tutorial papers, etc.) 518

Research exposition (monographs, survey articles) 614

Explicit machine computation and programs (not the theory of computation or programming) 18

Topological spaces and generalizations (closure spaces, etc.) 3140

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies) 1565

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.) 2379

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80] 2568

Special maps on topological spaces (open, closed, perfect, etc.) 4039

Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15] 1182

Connected and locally connected spaces (general aspects) 1469

Lower separation axioms ($T_0$--$T_3$, etc.) 2126

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.) 1908

Noncompact covering properties (paracompact, Lindelöf, etc.) 3682

Extensions of spaces (compactifications, supercompactifications, completions, etc.) 2828

Special constructions of spaces (spaces of ultrafilters, etc.) 419

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05] 1513