Geometry and combinatorics related to vector partition functions
Going down in (semi)lattices of finite Moore families and convex geometries
In this paper we first study what changes occur in the posets of irreducible elements when one goes from an arbitrary Moore family (respectively, a convex geometry) to one of its lower covers in the lattice of all Moore families (respectively, in the semilattice of all convex geometries) defined on a finite set. Then we study the set of all convex geometries which have the same poset of join-irreducible elements. We show that this set—ordered by set inclusion—is a ranked join-semilattice and we...
Graph factorization, general triple systems, and cyclic triple systems.
Graphes d'amitié et plans en blocs symétriques
Graphic Splitting of Cographic Matroids
In this paper, we obtain a forbidden minor characterization of a cographic matroid M for which the splitting matroid Mx,y is graphic for every pair x, y of elements of M.
Graphs associated with codes of covering radius 1 and minimum distance 2.
Graphs for n-circular matroids
We give "if and only if" characterization of graphs with the following property: given n ≥ 3, edges of such graphs form matroids with circuits from the collection of all graphs with n fundamental cycles. In this way we refer to the notion of matroidal family defined by Simões-Pereira [2].
Graphs from Projective Planes.
Gray-ordered binary necklaces.
Gromov hyperbolicity of planar graphs
We prove that under appropriate assumptions adding or removing an infinite amount of edges to a given planar graph preserves its non-hyperbolicity, a result which is shown to be false in general. In particular, we make a conjecture that every tessellation graph of ℝ2 with convex tiles is non-hyperbolic; it is shown that in order to prove this conjecture it suffices to consider tessellation graphs of ℝ2 such that every tile is a triangle and a partial answer to this question is given. A weaker version...
Group actions on magic squares.
Group distances of Latin squares
Groupoids and the associative law. VII. Semigroup distance of SH-groupoids
Growing Apollonian packings.