Reverse Directed Triple Systems

Rebecca Calahan-Zijlstra1, Robert B.Gardner2
1Department of Mathematics and Statistics Middle Tennessee State University Murfreesboro, Tennessee 37312
2 Department of Mathematics East Tennessee State University Johnson City, Tennessee 37614

Abstract

A directed triple system of order \(v\) and index \(\lambda\),denoted \({DTS}_\lambda(v)\), is said to be reverse if it admits an automorphism consisting of \(v/2\) transpositions when \(v\) is even, or a fixed point and \((v-1)/2\) transpositions when \(v\) is odd. We give necessary and sufficient conditions for the existence of a reverse \({DTS}_\lambda(v)\) for all \(\lambda \geq 1\).