BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Combinatorics of the tree amplituhedron - Lauren Williams (UC Berk
 eley)
DTSTART:20180703T160000Z
DTEND:20180703T170000Z
UID:TALK106381@talks.cam.ac.uk
CONTACT:HoD Secretary\, DPMMS
DESCRIPTION:The tree amplituhedron A(n\, k\, m) is a geometric object gene
 ralizing the positive Grassmannian\, which was introduced by Arkani-Hamed 
 and Trnka in 2013 in order to give a geometric basis for the computation o
 f scattering amplitudes in N=4 supersymmetric YangMills theory. I will giv
 e a gentle introduction to the amplituhedron\, and then describe what it l
 ooks like in various special cases. For example\, one can use the theory o
 f sign variation and matroids to show that the amplituhedron A(n\, k\, 1) 
 can be identified with the complex of bounded faces of a cyclic hyperplane
  arrangement. I will also present some conjectures relating the amplituhed
 ron A(n\, k\, m) to combinatorial objects such as non-intersecting lattice
  paths and plane partitions. This is joint work with Steven Karp\, and par
 t of it is additionally joint work with Yan Zhang.\n\nThe lecture will be 
 followed by a wine reception in the Central Core\, CMS.\n\n
LOCATION:CMS\, MR2
END:VEVENT
END:VCALENDAR