18-XX Category theory; homological algebra {For commutative rings, see 13Dxx; for associative rings, see 16Exx; for groups, see 20Jxx; for topological groups and related structures, see 57Txx; for algebraic topology, see also 55Nxx, 55Uxx} 28776
54-00 General reference works (handbooks, dictionaries, bibliographies, etc.) pertaining to general topology 26
54-03 History of general topology [Consider also classification numbers pertaining to Section 01-XX] 360
54A10 Several topologies on one set (change of topology, comparison of topologies, lattices of topologies) 1667
54A20 Convergence in general topology (sequences, filters, limits, convergence spaces, nets, etc.) 2534
54A25 Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] {For ultrafilters, see 54D80} 2703
54C55 Absolute neighborhood extensor, absolute extensor, absolute neighborhood retract (ANR), absolute retract spaces (general properties) [See also 55M15] 1210
54D15 Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.) 2004
54F05 Linearly ordered topological spaces, generalized ordered spaces, and partially ordered spaces [See also 06B30, 06F30] 2294
54H05 Descriptive set theory (topological aspects of Borel, analytic, projective, etc. sets) [See also 03E15, 26A21, 28A05] 1608
54H13 Topological fields, rings, etc. (topological aspects) [See also 12Jxx] {For algebraic aspects, see 13Jxx, 16W80} 339
54H30 Applications of general topology to computer science (e.g., digital topology, image processing) [See also 68U03] 9