BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Drupal iCal API//EN
X-WR-CALNAME:Events items teaser
X-WR-TIMEZONE:America/Toronto
BEGIN:VTIMEZONE
TZID:America/Toronto
X-LIC-LOCATION:America/Toronto
BEGIN:DAYLIGHT
TZNAME:EDT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
DTSTART:20250309T070000
END:DAYLIGHT
BEGIN:STANDARD
TZNAME:EST
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
DTSTART:20241103T060000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
UID:69d00f2ded030
DTSTART;TZID=America/Toronto:20250425T153000
SEQUENCE:0
TRANSP:TRANSPARENT
DTEND;TZID=America/Toronto:20250425T163000
URL:https://uwaterloo.ca/combinatorics-and-optimization/events/tutte-colloq
 uium-ahmad-abdi-2
SUMMARY:Tutte colloquium-Ahmad Abdi
CLASS:PUBLIC
DESCRIPTION:TITLE:Strongly connected orientations and integer lattices\n\nS
 PEAKER:\n Ahmad Abdi\n\nAFFILIATION:\n London School of Economics and Poli
 tical Science\n\nLOCATION:\n MC 5501\n\nABSTRACT: Let D = (V\, A) be a dig
 raph whose underlying graph is\n2-edge-connected\, and let P be the polyto
 pe whose vertices are the\nincidence vectors of arc sets whose reversal ma
 kes D strongly\nconnected. We study the lattice theoretic properties of th
 e integer\npoints contained in a proper 'slanted' face F of P. We prove un
 der a\nmild necessary condition that the 0\,1 points in F contain\nan _i
 ntegral_ _basis _B\, i.e.\, B is linearly independent\, and every\ninteg
 ral vector in the linear of span of F is an integral linear\ncombination o
 f B. This result is surprising as the integer points in F\ndo not necessar
 ily form a _Hilbert basis_. \n\nOur result has consequences for head-disj
 oint strong orientations in\nhypergraphs\, and also to a famous conjecture
  by Woodall that the\nminimum size of a dicut of D\, say k\, is equal to t
 he maximum number of\ndisjoint dijoins. We prove a relaxation of this conj
 ecture\, by finding\nfor any odd prime number p\, a p-adic packing of dijo
 ins of value k and\nof support size at most 2|A|. We also prove that the a
 ll-ones vector\nbelongs to the lattice generated by the 0\,1 points in F\,
  where F is\nthe face of P satisfying x(C) = 1 for every minimum dicut C.\
 n\nThis is based on joint work with Gerard Cornuejols\, Siyue Liu\, and\nO
 lha Silina.\n\n \n\n 
DTSTAMP:20260403T190413Z
END:VEVENT
END:VCALENDAR