On the excedance number of colored permutation groups.
On the - and -triangle of the barycentric subdivision of a simplicial complex
For a simplicial complex we study the behavior of its - and -triangle under the action of barycentric subdivision. In particular we describe the - and -triangle of its barycentric subdivision . The same has been done for - and -vector of by F. Brenti, V. Welker (2008). As a consequence we show that if the entries of the -triangle of are nonnegative, then the entries of the -triangle of are also nonnegative. We conclude with a few properties of the -triangle of .
On the measurement of the (non)linearity of Costas permutations.
On the number of antichains of finite power sets
On the number of permutations arising from a problem in cell-biology.
On the permutations generated by cyclic shift.
On the permutations generated by Sturmian words.
On the semigroup of binary relations on a finite set
On the Stanley-Wilf conjecture for the number of permutations avoiding a given pattern.
On the subspace of .
On weak convergence of sequences of measures
Operads and algebraic combinatorics of trees.