A Characterization of Designs Related to the Witt System S(5, 8, 24).
Using the Kramer-Mesner method, - designs with as a group of automorphisms and with in the set are constructed. The search uses specific partitioning of columns of the orbit incidence matrix, related to so-called “quasi-designs”. Actions of groups , and twisted are being compared. It is shown that there exist - designs with , respectively twisted as a group of automorphisms and with in the set . With in the set , there exist designs which possess all three considered groups...
This article presents the principal results of the Ph.D. thesis Investigation and classification of doubly resolvable designs by Stela Zhelezova (Institute of Mathematics and Informatics, BAS), successfully defended at the Specialized Academic Council for Informatics and Mathematical Modeling on 22 February 2010.The resolvability of combinatorial designs is intensively investigated because of its applications. This research focuses on resolvable designs with an additional property - they have resolutions...