Presented by: 
David Pike, Memorial University of Newfoundland
Tue 24 Jan, 3:00 pm - 4:00 pm

A $\lambda$-fold triple system of order $v$ consists of a $v$-set $V$ and
a collection of 3-subsets (called blocks or triples) of $V$ such that each
2-subset of $V$ occurs in exactly $\lambda$ of the system's triples.
Given a $\lambda$-fold triple system with $\lambda > 1$, we can ask
whether its triples can be ordered so that the union of any two
consecutive triples consists of four elements of $V$.  We will describe
some potential applications, briefly review previous results, and discuss
some recent work concerning the nonexistence / existence of such
orderings, with emphasis on 2-fold triple systems.  This is joint work
with Aras Erzurumluo\u{g}lu.