Weight multiplicity polynomials for affine Kac-Moody algebras of type
Weighted spanning trees on some self-similar graphs.
Weights of partitions and character zeros.
Well-rounded sublattices of planar lattices
A lattice in Euclidean d-space is called well-rounded if it contains d linearly independent vectors of minimal length. This class of lattices is important for various questions, including sphere packing or homology computations. The task of enumerating well-rounded sublattices of a given lattice is of interest already in dimension 2, and has recently been treated by several authors. In this paper, we analyse the question more closely in the spirit of earlier work on similar sublattices and coincidence...
When can the sum of th of the binomial coefficients have closed form.
When is the orbit algebra of a group an integral domain ? Proof of a conjecture of P.J. Cameron
Cameron introduced the orbit algebra of a permutation group and conjectured that this algebra is an integral domain if and only if the group has no finite orbit. We prove that this conjecture holds and in fact that the age algebra of a relational structure R is an integral domain if and only if R is age-inexhaustible. We deduce these results from a combinatorial lemma asserting that if a product of two non-zero elements of a set algebra is zero then there is a finite common tranversal of their...
When structures are almost surely connected.
Where the typical set partitions meet and join.
Why the characteristic polynomial factors.
Wild partitions and number theory.
Wilf classes of pairs of permutations of length 4.
Wilf-equivalence on -ary words, compositions, and parking functions.
William Chen grammars and derivations in trees and arborescences. (Grammaires de William Chen et dérivations dans les arbres et arborescences.)
Winning paths in -by-infinity Hex.
Words avoiding a reflexive acyclic relation.
Words restricted by patterns with at most 2 distinct letters.
Wreath products of permutation classes.