Rectangular and trapezoidal arrangements.
Recursive constructions for skew resolutions in affine geometries.
Recursive Methods for Construction of Balanced N-ary Block Designs
2000 Mathematics Subject Classification: Primary 05B05; secondary 62K10.This paper presents a recursive method for the construction of balanced n-ary block designs. This method is based on the analogy between a balanced incomplete binary block design (B.I .E .B) and the set of all distinct linear sub-varieties of the same dimension extracted from a finite projective geometry. If V1 is the first B.I .E .B resulting from this projective geometry, then by regarding any block of V1 as a projective geometry,...
Reducing a set by subtracting squares.
Regular conditional linear spaces with two consecutive line degrees.
Regular elements of the semigroup of all binary relations.
Regular linear spaces.
Regularly Derived Planes.
Regulated buildups of 3-configurations
We deal with two types of buildups of 3-configurations: a generating buildup over a given edge set and a regulated one (according to maximal relative degrees of vertices over a penetrable set of vertices). Then we take account to minimal generating edge sets, i.e., to edge bases. We also deduce the fundamental relation between the numbers of all vertices, of all edges from edge basis and of all terminal elements. The topic is parallel to a certain part of Belousov' “Configurations in algebraic...
Relations, coverings, hypergraphs and matroids
Relationships between conbinatorics and 0-simple semigroups.
Relativnullen und reduzible Mengen bei Differenzen von Mengen ganzer Zahlen.
Remark to a problem on 0-1 matrices
Remarks on factorizations in algebraic number fields
Repeated patterns of dense packings of equal disks in a square.
Resolvable Mendelsohn designs with block size 4.
Resolving triple systems into regular configurations.
Restricted and quasi-toral restricted Lie-Rinehart algebras
In this paper, we introduce the definition of restrictable Lie-Rinehart algebras, the concept of restrictability is by far more tractable than that of a restricted Lie-Rinehart algebra. Moreover, we obtain some properties of p-mappings and restrictable Lie-Rinehart algebras. Finally, we give some sufficient conditions for the commutativity of quasi-toral restricted Lie-Rinehart algebras and study how a quasi-toral restricted Lie-Rinehart algebra with zero center and of minimal dimension should be....
Rhombus tilings of a hexagon with two triangles missing on the symmetry axis.
Rigidité des empilements infinis immergés proprement dans le plan et dans le disque