 PHD CONFIRMATION SEMINAR
 Speaker: Andrew Goh, The University of Newcastle
 Title: Pattern avoiding permutations
 Location: Room V206, Mathematics Building (Callaghan Campus) The University of Newcastle
 Time and Date: 10:00 am, Wed, 7^{th} Jun 2017
 Abstract:
The research interest in pattern avoiding permutations is
inspired by Donald Knuth’s work in stacksorting. According to Knuth,
a permutation can be sorted by passing through a single infinite stack
if and only if it avoids a subpermutation pattern 231. Murphy
extended Knuth’s research by using two infinite stacks in series and
found out that the basis for generated permutations is infinite but
Elder proved that the basis is finite when one of the stack is limited
to depth two and the permutations are algebraic. My research is to
investigate the permutations generated by a stack of depth 3 and an
infinite stack in series. It is to determine the basis and nature of
the permutations in term of formal language.
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 CARMA SEMINAR
 Speaker: Andrew Goh, The University of Newcastle
 Title: Solving free group equations on a computer
 Location: Room V205, Mathematics Building (Callaghan Campus) The University of Newcastle
 Dates: Wed, 30^{th} Nov 2016  Wed, 30^{th} Nov 2016
 Abstract:
I will discuss how to solve free group equations using a practical computer program. Ciobanu, Diekert and Elder recently gave a theoretical algorithm which runs in nondeterministic space $n\log n$, but implementing their method as an actual computer program presents many challenges, which I will describe.
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