EJC
2007
13 years 8 months ago
2007
Abstract. We extend the Cayley-Sylvester formula for symmetric powers of SL2(C)modules, to plethysms defined by rectangle partitions. Ordinary partitions are replaced by plane par...
EJC
2007
13 years 8 months ago
2007
Balanced incomplete-block designs (BIBDs) with repeated blocks are studied and constructed. We continue work initiated by van Lint and Ryser in 1972 and pursued by van Lint in 197...
EJC
2007
13 years 8 months ago
2007
EJC
2007
13 years 8 months ago
2007
We present results on the size of the smallest maximal partial ovoids and on the size of the smallest maximal partial spreads of the generalized quadrangles W(q) and Q(4, q). Key ...
EJC
2007
13 years 8 months ago
2007
We study the notion of hypertree width of hypergraphs. We prove that, up to a constant factor, hypertree width is the same as a number of other hypergraph invariants that resemble...
EJC
2007
13 years 8 months ago
2007
Let K− r denote the graph obtained from Kr by deleting one edge. We show that for every integer r ≥ 4 there exists an integer n0 = n0(r) such that every graph G whose order n ...
EJC
2007
13 years 8 months ago
2007
EJC
2007
13 years 8 months ago
2007
Jim Propp’s P-machine, also known as the ‘rotor router model’ is a simple deterministic process that simulates a random walk on a graph. Instead of distributing chips to ran...
EJC
2007
13 years 8 months ago
2007
Given a graph we show how to construct a family of manifolds whose Euler characteristics are the values of the chromatic polynomial of the graph at various integers. The manifolds...
EJC
2007
13 years 8 months ago
2007
Let Φ be an irreducible root system and ∆ be a base for Φ; it is well known that any root in Φ is an integral combination of the roots in ∆. In comparison to this fact, we ...