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Cyclic, Simple, and Indecomposable Three-fold Triple Systems

Nabil Shalaby1, Bradley Sheppard1, Daniela Silvesan1
1Department of Mathematics and Statistics Memorial University of Newfoundland St. John’s, Newfoundland CANADA A1C 587

Abstract

In 2000, Rees and Shalaby constructed simple indecomposable two-fold cyclic triple systems for all \(v \equiv 0, 1, 3, 4, 7, \text{ and } 9 \pmod{12}\) where \(v = 4\) or \(v \geq 12\), using Skolem-type sequences.
We construct, using Skolem-type sequences, three-fold triple systems having the properties of being cyclic, simple, and indecomposable for all admissible orders \(v\), with some possible exceptions for \(v = 9\) and \(v = 24c + 57\), where \(c \geq 2\) is a constant.

Keywords: cyclic triple systems; Skolem-type sequences; 4-fold triple systems; indecomposable and simple designs MSC Classification: 05B