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SUMMARY:Vladimir Chernov (Dartmouth College)
DTSTART:20240313T140000Z
DTEND:20240313T150000Z
DTSTAMP:20260416T020839Z
UID:PHK-cohomology-seminar/98
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/PHK-cohomolo
 gy-seminar/98/">Virtual Legendrian knots and possible relations to causali
 ty in Borde–Sorkin spacetimes</a>\nby Vladimir Chernov (Dartmouth Colleg
 e) as part of Prague-Hradec Kralove seminar Cohomology in algebra\, geomet
 ry\, physics and statistics\n\n\nAbstract\nWe review our results with Stef
 an Nemirovski on the relation\nof Legendrian linking and causal structure 
 in globally hyperbolic\nspacetimes. After that we discuss virtual Legendri
 an knots defined as\nLegendrian knots in $ST^∗M$ studied up to isotopy a
 nd modification of\n$ST^∗M$ induced by surgery on M that were introduced
  by Patricia Cahn\nand Asa Levi. We formulate a few conjectures about them
  and\nconjecturally relate them to causality in Borde–Sorkin spacetimes 
 that\nare manifolds with a Lorentz metric that is degenerate at critical\n
 points of a Morse "timelike" function and that consist of globally\nhyperb
 olic pieces between critical levels. We prove these conjectures\nfor 2+1 d
 imensional Borde–Sorkin spacetimes.\nThe talk is based on the joint work
  with Rustam Sadykov.\n
LOCATION:https://researchseminars.org/talk/PHK-cohomology-seminar/98/
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