54A10 Several topologies on one set (change of topology, comparison of topologies, lattices of topologies) 1775
54A20 Convergence in general topology (sequences, filters, limits, convergence spaces, nets, etc.) 2681
54A25 Cardinality properties (cardinal functions and inequalities, discrete subsets) [See also 03Exx] {For ultrafilters, see 54D80} 2800