On translation transversal designs
On two- and three-element subsets of groups.
On zero free sets.
On π-Groupoids
One-adhesive polymatroids
Adhesive polymatroids were defined by F. Matúš motivated by entropy functions. Two polymatroids are adhesive if they can be glued together along their joint part in a modular way; and are one-adhesive, if one of them has a single point outside their intersection. It is shown that two polymatroids are one-adhesive if and only if two closely related polymatroids have joint extension. Using this result, adhesive polymatroid pairs on a five-element set are characterized.
On-line Covering the Unit Square with Squares
The unit square can be on-line covered with any sequence of squares whose total area is not smaller than 4.
On-line Packing Squares into n Unit Squares
If n ≥ 3, then any sequence of squares of side lengths not greater than 1 whose total area does not exceed ¼(n+1) can be on-line packed into n unit squares.
Optimal mixed Factorial Resolution III designs
Optimisation hybride par colonies de fourmis pour le problème de découpe à deux dimensions
Nous nous intéressons dans cet article au problème de découpe guillotine en deux dimensions noté 2BP/O/G. Il s'agit de découper un certain nombre de pièces rectangulaires dans un ensemble de plaques de matière première, elles même rectangulaires et identiques. Celles-ci sont disponibles en quantité illimitée. L'objectif est de minimiser le nombre de plaques utilisées pour satisfaire la demande, en appliquant une succession de coupes, dites guillotines, allant de bout en bout. Nous proposons une approche...
Optimum chemical balance weighing designs under the restriction on weighings
The paper deals with the problem of estimating individual weights of objects, using a chemical balance weighing design under the restriction on the number in which each object is weighed. A lower bound for the variance of each of the estimated weights from this chemical balance weighing design is obtained and a necessary and sufficient condition for this lower bound to be attained is given. The incidence matrix of ternary balanced block design is used to construct optimum chemical balance weighing...
Orientable self-embeddings of Steiner triple systems of order 15.
Oriented matroids in terms of order functions.
Oriented matroids today.
Oriented Matroids with Few Mutations.
Orthogonal arrays with parameters OA and 3-dimensional projective geometries.
Orthogonal colorings of graphs.
Orthogonal designs II.
Orthogonal double covers of complete graphs by fat caterpillars
An orthogonal double cover (ODC) of the complete graph Kₙ by some graph G is a collection of n spanning subgraphs of Kₙ, all isomorphic to G, such that any two of the subgraphs share exactly one edge and every edge of Kₙ is contained in exactly two of the subgraphs. A necessary condition for such an ODC to exist is that G has exactly n-1 edges. We show that for any given positive integer d, almost all caterpillars of diameter d admit an ODC of the corresponding complete graph.
Orthogonal packings in PG(5, 2).
Orthogonal partitions and covering of graphs