We investigate the spectrum for {4}-GDDs of type g u m
1. We determine, for each admissible pair (g, u) (with some exceptions), the maximum and minimum values of m for which a {4}-GDD of type g u m 1 exists.
Abstract. The derived category D(ModA) of a Gorenstein triangular matrix algebra A admits an unbounded ladder; and this ladder restricts toleft recollement of triangulated categories with Serre functors sits in a ladder of period 1; as an application, the singularity category of A admits a ladder of period 1.
Recollements ([BBD]
We investigate several antipodal spherical designs on whether we can choose half of the points, one from each antipodal pair, such that they are balanced at the origin. In particular, root systems of type A, D and E, minimal points of Leech lattice and the unique tight 7-design on S 22 are studied. We also study a half of an antipodal spherical design from the viewpoint of association schemes and spherical designs of harmonic index T .1991 Mathematics Subject Classification. 05B30, 05B35.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.