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Discrete Mathematics and Combinatorics Commons

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Full-Text Articles in Discrete Mathematics and Combinatorics

Almost Difference Sets And Reversible Divisible Difference Sets, James A. Davis Dec 1992

Almost Difference Sets And Reversible Divisible Difference Sets, James A. Davis

Department of Math & Statistics Faculty Publications

Let G be a group of order mn and N a subgroup of G of order n. If D is a k-subset of G, then D is called a (m, n, k, λ1, λ2) divisible difference set (DDS) provided that the differences dd'-1 for d, d'D, d ≠ d' contain every nonidentity element of N exactly λ1 times and every element of G - N exactly λ2 times. Difference sets are used to generate designs, as described by [4] and [9]. D will be …


Construction Of Relative Difference Sets In P-Groups, James A. Davis May 1992

Construction Of Relative Difference Sets In P-Groups, James A. Davis

Department of Math & Statistics Faculty Publications

Jungnickel (1982) and Elliot and Butson (1966) have shown that (pj+1,p,pj+1,pj) relative difference sets exist in the elementary abelian p-group case (p an odd prime) and many 2-groups for the case p = 2. This paper provides two new constructions of relative difference sets with these parameters; the first handles any p-group (including non-abelian) with a special subgroup if j is odd, and any 2-group with that subgroup if j is even. The second construction shows that if j is odd, every abelian group …


An Exponent Bound For Relative Difference Sets In P-Groups, James A. Davis Jan 1992

An Exponent Bound For Relative Difference Sets In P-Groups, James A. Davis

Department of Math & Statistics Faculty Publications

An exponent bound is presented for abelian (pi+j, pi, pi+j, pi) relative difference sets: this bound can be met for ij.