We give a version for oriented matroids of the following problem of McMullen: 'Determine the largest number a(d) such that a(d) points, lying in general position in !R, may be mapped by a permissibleâ€¦ (More)

We formulate and study a necessary and sufficient condition for a configuration of any type of infinite additive cellular automata to have periodic behavior in time. The number of orbits with periodâ€¦ (More)

In this paper we consider the cocircuit graph G M of an oriented matroid M, the 1-skeleton of the cell complex W formed by the span of the cocircuits of M. In general,W is not determined by G M.â€¦ (More)

Consider the moment curve in the real Euclidean space R defined parametrically by the map Î³ : R â†’ R, t â†’ Î³(t) = (t, t, . . . , t). The cyclic d-polytope Cd(t1, . . . , tn) is the convex hull of theâ€¦ (More)

Let V be a vector space of dimension d over a field K and let A be a central arrangement of hyperplanes in V . To answer a question posed by K. Aomoto, P. Orlik and H. Terao construct a commutativeâ€¦ (More)

LetM =M(E) be a matroid on a linear ordered set E. The Orlikâ€“SolomonZ-algebra OS(M) of M is the free exteriorZ-algebraon E, modulo the ideal generated by the circuit boundaries. TheZ-module OS(M) hasâ€¦ (More)