## Mathematical Subject Classification – MSC2010

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

Instructional exposition (textbooks, tutorial papers, etc.)
514

Research exposition (monographs, survey articles)
608

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

Topological spaces and generalizations (closure spaces, etc.)
3089

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies)
1544

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.)
2359

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80]
2555

Special maps on topological spaces (open, closed, perfect, etc.)
4017

Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15]
1175

Connected and locally connected spaces (general aspects)
1456

Lower separation axioms ($T_0$--$T_3$, etc.)
2104

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.)
1898

Noncompact covering properties (paracompact, Lindelöf, etc.)
3657

Extensions of spaces (compactifications, supercompactifications, completions, etc.)
2809

Special constructions of spaces (spaces of ultrafilters, etc.)
411

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05]
1500