A multiplier theorem for projections of affine difference sets
Let \(R\) be a relative \((m,n,m-1,(m-2)/n)\)-difference set in an abelian group \(G\) (with \(|G|=nm\), \(|R|=m-1\)). Then \(m-1\) is a multiplier of \(R\). If \(m-1=p^iq^j\) (\(p,q\) prime numbers) then \(p^i\) and \(q^j\) are multipliers of \(R\). Moreover \(-1\) cannot be a multiplier of \(R\). There are several wrong proofs of the last result in the literature.
multipliers for relative difference sets
scientific article; zbMATH DE number 1057367