منابع مشابه
Distorting symmetric designs
A simple replacement approach is used to construct new symmetric and affine designs from projective or affine spaces. This is used to construct symmetric designs with a given automorphism group, to study GMW-designs, and to construct new affine designs whose automorphism group fixes a point and has just two pointand block-orbits.
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This paper is of an investigation of symmetric 2 (v, k,'x) designs such that the point set and the block set can each be halved to give a tactical decomposition. We assume that there is a group of automorphisms of the design of order v /2 which has two orbits of points, each of length v /2. Only the identity fixes a point, and we say that such a group acts half-regularly on the design. The desi...
متن کاملDecomposable symmetric designs
The first infinite families of symmetric designswere obtained fromfinite projective geometries, Hadamardmatrices, and difference sets. In this paper we describe two general methods of constructing symmetric designs that give rise to the parameters of all other known infinite families of symmetric designs. The method of global decomposition produces an incidence matrix of a symmetric design as a...
متن کاملArtifacts for Stamping Symmetric Designs
It is well known that there are 17 crystallographic groups that determine the possible tessellations of the Euclidean plane. We approach them from an unusual point of view. Corresponding to each crystallographic group there is an orbifold. We show how to think of the orbifolds as artifacts that serve to create tessellations. 1. TESSELLATIONS. The history of human civilization gives an enormous ...
متن کاملImprimitive flag-transitive symmetric designs
A recent paper of O’Reilly Regueiro obtained an explicit upper bound on the number of points of a flagtransitive, point-imprimitive, symmetric design in terms of the number of blocks containing two points. We improve that upper bound and give a complete list of feasible parameter sequences for such designs for which two points lie in at most ten blocks. Classifications are available for some of...
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ژورنال
عنوان ژورنال: Designs, Codes and Cryptography
سال: 2008
ISSN: 0925-1022,1573-7586
DOI: 10.1007/s10623-008-9209-3