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DTSTART:20190331T030000
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DTSTART:20181028T020000
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DTSTAMP:20190722T142508Z
UID:59e3891f8f5af450319984@ist.ac.at
DTSTART:20190306T130000
DTEND:20190306T141500
DESCRIPTION:Speaker: Emo Welzl\nhosted by Uli Wagner\nAbstract: We investig
ate the connectivity of the flip-graph of all (full ) triangulations of a
given finite planar point set P in general position and prove that\, for n
:=|P| large enough\, both edge- and vertex-connectivity are determined by
the minimum degree occurring in the flip-graph\, i.e. the minimum number o
f flippable edges in any triangulation of P. It is known that every triang
ulation allows at least (n-4)/2 edge-flips.This result is extended to so-c
alled subtriangulations\, i.e. the set of all triangulations of subsets of
P which contain all extreme points of P\, where the flip operation is ext
ended to bistellar flips (edge-flips\, and insertion and removal of an inn
er vertex of degree three). Here we prove (n-3)-edge-connectedness (for al
l P) and (n-3)-vertex-connectedness of n large enough ((n-3) is tight\, si
nce there is always a subtriangulation which allows exactly $n-3$ bistella
r flips). This matches the situation known (through the secondary polytope
) for so-called regular triangulations.(joint work with Uli Wagner\, IST A
ustria)
LOCATION:Mondi Seminar Room 3\, Central Building\, IST Austria
ORGANIZER:hwagner@ist.ac.at
SUMMARY:GeomTop Seminar: Connectivity of the Flip-Graph of Triangulations
URL:https://talks-calendar.app.ist.ac.at/events/1838
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