On a generalization of the Narayana triangle.
On a New Approach to Williamson's Generalization of Pólya's Enumeration Theorem
Pólya’s fundamental enumeration theorem and some results from Williamson’s generalized setup of it are proved in terms of Schur- Macdonald’s theory (S-MT) of “invariant matrices”. Given a permutation group W ≤ Sd and a one-dimensional character χ of W , the polynomial functor Fχ corresponding via S-MT to the induced monomial representation Uχ = ind|Sdv/W (χ) of Sd , is studied. It turns out that the characteristic ch(Fχ ) is the weighted inventory of some set J(χ) of W -orbits in the integer-valued hypercube...
On a new family of generalized Stirling and Bell numbers.
On a number pyramid related to the binomial, Deleham, Eulerian, MacMahon and Stirling number triangles.
On a partition function of Richard Stanly.
On a Problem of D'Atri and Nickerson.
On a problem of Steinhaus concerning binary sequences.
On a question of K. Leeb
On A System Of All Maximal Chains (Antichains) Of A Graph
On an extension of Euler numbers and records of alternating permutations. (Sur une extension des nombres d'Euler et les records des permutations alternantes.)
On an identity for the cycle indices of rooted tree automorphism groups.
On an integer sequence related to a product of trigonometric functions, and its combinatorial relevance.
On an open problem of Green and Losonczy: exact enumeration of freely braided permutations.
On Arrangements of Jordan Arcs with Three Intersections per Pair.
On binary trees and Dyck paths
A bijection between the set of binary trees with n vertices and the set of Dyck paths of length 2n is obtained. Two constructions are given which enable to pass from a Dyck path to a binary tree and from a binary tree to a Dyck path.
On binary trees and permutations
Every binary tree is associated to a permutation with repetitions, which determines it uniquely. Two operations are introduced and used for the construction of the set of all binary trees. The set of all permutations which correspond to a given binary tree is determined and its cardinal number is evaluated.
On coefficients of circuit polynomials and characteristic polynomials.
On counting of periodic words. (Zur Abzählung periodischer Worte.)
On counting permutations by pairs of congruence classes of major index.
On descents in standard Young tableaux.