## Mathematical Subject Classification – MSC2010

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

Instructional exposition (textbooks, tutorial papers, etc.)
511

Research exposition (monographs, survey articles)
609

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

Topological spaces and generalizations (closure spaces, etc.)
3066

Several topologies on one set (change of topology, comparison of topologies, lattices of topologies)
1528

Convergence in general topology (sequences, filters, limits, convergence spaces, etc.)
2348

Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] [For ultrafilters, see 54D80]
2547

Special maps on topological spaces (open, closed, perfect, etc.)
3997

Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15]
1174

Connected and locally connected spaces (general aspects)
1450

Lower separation axioms ($T_0$--$T_3$, etc.)
2092

Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.)
1890

Noncompact covering properties (paracompact, Lindelöf, etc.)
3637

Extensions of spaces (compactifications, supercompactifications, completions, etc.)
2799

Special constructions of spaces (spaces of ultrafilters, etc.)
408

Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05]
1496