1,477 research outputs found
Sets of Complex Unit Vectors with Two Angles and Distance-Regular Graphs
We study {0,\alpha}-sets, which are sets of unit vectors of in
which any two distinct vectors have angle 0 or \alpha. We investigate some
distance-regular graphs that provide new constructions of {0,\alpha}-sets using
a method by Godsil and Roy. We prove bounds for the sizes of {0,\alpha}-sets of
flat vectors, and characterize all the distance-regular graphs that yield
{0,\alpha}-sets meeting the bounds at equality.Comment: 15 page
Partial geometric designs and difference families
We examine the designs produced by different types of difference families. Difference families have long been known to produce designs with well behaved automorphism groups. These designs provide the elegant solutions desired for applications. In this work, we explore the following question: Does every (named) design have a difference family analogue? We answer this question in the affirmative for partial geometric designs
- …