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CATEGORIES:The LMS Hardy Lecture
SUMMARY:Combinatorics of the tree amplituhedron - Lauren W
illiams (UC Berkeley)
DTSTART;TZID=Europe/London:20180703T170000
DTEND;TZID=Europe/London:20180703T180000
UID:TALK106381AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/106381
DESCRIPTION:The tree amplituhedron A(n\, k\, m) is a geometric
object generalizing the positive Grassmannian\, w
hich was introduced by Arkani-Hamed and Trnka in 2
013 in order to give a geometric basis for the com
putation of scattering amplitudes in N=4 supersymm
etric YangMills theory. I will give a gentle intro
duction to the amplituhedron\, and then describe w
hat it looks like in various special cases. For ex
ample\, one can use the theory of sign variation a
nd matroids to show that the amplituhedron A(n\, k
\, 1) can be identified with the complex of bounde
d faces of a cyclic hyperplane arrangement. I will
also present some conjectures relating the amplit
uhedron A(n\, k\, m) to combinatorial objects such
as non-intersecting lattice paths and plane parti
tions. This is joint work with Steven Karp\, and p
art of it is additionally joint work with Yan Zhan
g.\n\nThe lecture will be followed by a wine recep
tion in the Central Core\, CMS.\n\n
LOCATION:CMS\, MR2
CONTACT:HoD Secretary\, DPMMS
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