7 on Tight Projective Designs
نویسنده
چکیده
It is shown that among all tight designs in FP n = RP 1 , where F is R or C, or H (quaternions), only 5-designs in CP 1 [14] have irrational angle set. This is the only case of equal ranks of the first and the last irreducible idempotent in the corresponding Bose-Mesner algebra.
منابع مشابه
Flag-transitive Point-primitive symmetric designs and three dimensional projective special linear groups
The main aim of this article is to study (v,k,λ)-symmetric designs admitting a flag-transitive and point-primitive automorphism group G whose socle is PSL(3,q). We indeed show that the only possible design satisfying these conditions is a Desarguesian projective plane PG(2,q) and G > PSL(3,q).
متن کامل1-Designs from the group $PSL_{2}(59)$ and their automorphism groups
In this paper, we consider the projective special linear group $PSL_2(59)$ and construct some 1-designs by applying the Key-Moori method on $PSL_2(59)$. Moreover, we obtain parameters of these designs and their automorphism groups. It is shown that $PSL_2(59)$ and $PSL_2(59):2$ appear as the automorphism group of the constructed designs.
متن کاملThe Nonexistence of Certain Tight Spherical Designs
In this paper, the nonexistence of tight spherical designs is shown in some cases left open to date. Tight spherical 5-designs may exist in dimension n = (2m + 1)2 − 2, and the existence is known only for m = 1, 2. In the paper, the existence is ruled out under a certain arithmetic condition on the integer m, satisfied by infinitely many values of m, including m = 4. Also, nonexistence is shown...
متن کاملSpin-embeddings, two-intersection sets and two-weight codes
Let ∆ be one of the dual polar spaces DQ(8, q), DQ−(7, q), and let e : ∆ → Σ denote the spin-embedding of ∆. We show that e(∆) is a two-intersection set of the projective space Σ. Moreover, if ∆ ∼= DQ−(7, q), then e(∆) is a (q + 1)-tight set of a nonsingular hyperbolic quadric Q(7, q) of Σ ∼= PG(7, q). This (q + 1)-tight set gives rise to more examples of (q + 1)-tight sets of hyperbolic quadri...
متن کامل1 1 Ju l 2 00 3 The Theory of Tight Closure from the Viewpoint of Vector Bundles
Contents Introduction 3 1. Foundations 13 1.1. A survey about the theory of tight closure 13 1.2. Solid closure and forcing algebras 23 1.3. Cohomological dimension 25 1.4. Vector bundles, locally free sheaves and projective bundles 28 2. Geometric interpretation of tight closure via bundles 30 2.1. Relation bundles 30 2.2. Affine-linear bundles arising from forcing algebras 32 2.3. Cohomology ...
متن کامل