activity
19922024
most citedUltrafilters: Where topological dynamics = algebra = combinatorics

32 citations · 206 across the 50 of their papers we have counts for

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Showing 1998Show all

2 papers · 1 filter

math.CO1998

Mobius functions of lattices

Andreas Blass, Bruce E. Sagan

We introduce the concept of a bounded below set in a lattice. This can be used to give a generalization of Rota's broken circuit theorem to any finite lattice. We then show how thi…

math.CO1998★ 10 cited

Characteristic and Ehrhart polynomials

Andreas Blass, Bruce E. Sagan

Let A be a subspace arrangement and let chi(A,t) be the characteristic polynomial of its intersection lattice L(A). We show that if the subspaces in A are taken from L(B_n), where…