## Mathematics Subject Classification – MSC2010

General reference works (handbooks, dictionaries, bibliographies, etc.) 27

Instructional exposition (textbooks, tutorial papers, etc.) 519

Research exposition (monographs, survey articles) 623

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

Topological spaces and generalizations (closure spaces, etc.) 3196

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies) 1582

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.) 2417

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80] 2595

Special maps on topological spaces (open, closed, perfect, etc.) 4073

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) 1490

Lower separation axioms ($T_0$--$T_3$, etc.) 2166

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.) 1930

Noncompact covering properties (paracompact, Lindelöf, etc.) 3719

Extensions of spaces (compactifications, supercompactifications, completions, etc.) 2851

Special constructions of spaces (spaces of ultrafilters, etc.) 438

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05] 1535