A combinatorial theorem for a symmetric triangulation of the sphere
A common recursion for Laplacians of matroids and shifted simplicial complexes.
A comparison of two upper bounds on the permanent of -matrices. (Ein Vergleich zweier oberer Schranken für die Permanente von -Matrizen.)
A complete annotated bibliography of work related to Sidon sequences.
A Conjecture Concerning The Existence Of Certain Combinatorial Designs.
A connection between ordinary partitions and tilings with dominoes and squares.
A construction method for complete sets of mutually orthogonal frequency squares.
A construction method for generalized Room squares.
A construction method for generalized Room squares. (Short Communication).
A construction of resolvable quadruple systems
A determinant formula from random walks
One usually studies the random walk model of a cat moving from one room to another in an apartment. Imagine now that the cat also has the possibility to go from one apartment to another by crossing some corridors, or even from one building to another. That yields a new probabilistic model for which each corridor connects the entrance rooms of several apartments. This article computes the determinant of the stochastic matrix associated to such random walks. That new model naturally allows to compute...
A discrete Fourier kernel and Fraenkel's tiling conjecture
A family of 4-designs on 26 points
Using the Kramer-Mesner method, - designs with as a group of automorphisms and with in the set are constructed. The search uses specific partitioning of columns of the orbit incidence matrix, related to so-called “quasi-designs”. Actions of groups , and twisted are being compared. It is shown that there exist - designs with , respectively twisted as a group of automorphisms and with in the set . With in the set , there exist designs which possess all three considered groups...
A family of complete arcs in finite projective planes
A few more cyclic Steiner 2-designs.
A forbidden-suborder characterization of binarily-composable diagrams in double categories.
A further look into combinatorial orthogonality.
A generalization of group difference sets and the matrix equation Am = dI + ...J.
A generalization of transversals for Latin squares.
A Generalized Mean-Value Theorem.