Signed Difference Sets

Daniel M. Gordon

A $(v,k,\lambda )$ difference set in a group $G$ of order $v$ is a subset $\{d_1,d_2,\dots ,d_k\}$ of $G$ such that $D=\sum d_i$ in the group ring $\mathbb{Z}[G]$ satisfies $$D D^{-1} =…