Columbia subject headings:
Combinatorial enumeration problems--Congresses.
Combinatorial geometry--Congresses.
Homology theory--Congresses.
Harvard subject headings:
Combinatorial enumeration problems--Congresses.
Combinatorial geometry--Congresses.
Homology theory--Congresses.
Orlik, Peter, 1938---Congresses.
Princeton subject headings:
Combinatorial enumeration problems.
Combinatorial geometry.
Lattice theory.