## Mathematics Subject Classification – MSC2010

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

Instructional exposition (textbooks, tutorial papers, etc.) 520

Research exposition (monographs, survey articles) 616

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

Topological spaces and generalizations (closure spaces, etc.) 3178

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies) 1573

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.) 2395

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80] 2587

Special maps on topological spaces (open, closed, perfect, etc.) 4053

Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15] 1185

Connected and locally connected spaces (general aspects) 1478

Lower separation axioms ($T_0$--$T_3$, etc.) 2147

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.) 1918

Noncompact covering properties (paracompact, Lindelöf, etc.) 3708

Extensions of spaces (compactifications, supercompactifications, completions, etc.) 2844

Special constructions of spaces (spaces of ultrafilters, etc.) 429

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05] 1525