Abstract simplicial complexW
Abstract simplicial complex
AntimatroidW
Antimatroid
Dedekind numberW
Dedekind number
Disjoint setsW
Disjoint sets
Generalized quadrangleW
Generalized quadrangle
HypergraphW
Hypergraph
Incidence structureW
Incidence structure
Kirkman's schoolgirl problemW
Kirkman's schoolgirl problem
Levi graphW
Levi graph
Near polygonW
Near polygon
Noncrossing partitionW
Noncrossing partition
Partition of a setW
Partition of a set
Sauer–Shelah lemmaW
Sauer–Shelah lemma
Steiner systemW
Steiner system
UltrafilterW
Ultrafilter
Universe (mathematics)W
Universe (mathematics)