## Mathematical Subject Classification – MSC2010

General reference works (handbooks, dictionaries, bibliographies, etc.)
28

Instructional exposition (textbooks, tutorial papers, etc.)
508

Research exposition (monographs, survey articles)
608

Explicit machine computation and programs (not the theory of computation or programming)
19

Topological spaces and generalizations (closure spaces, etc.)
3043

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies)
1522

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.)
2338

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80]
2542

Special maps on topological spaces (open, closed, perfect, etc.)
3990

Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15]
1171

Connected and locally connected spaces (general aspects)
1444

Lower separation axioms ($T_0$--$T_3$, etc.)
2085

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.)
1884

Noncompact covering properties (paracompact, Lindelöf, etc.)
3627

Extensions of spaces (compactifications, supercompactifications, completions, etc.)
2791

Special constructions of spaces (spaces of ultrafilters, etc.)
406

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05]
1493