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SUMMARY:Kouki Sato
DTSTART:20201130T150000Z
DTEND:20201130T160000Z
DTSTAMP:20260423T024529Z
UID:mitgt/8
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/mitgt/8/">Fi
 ltered instanton Floer homology and the homology cobordism group</a>\nby K
 ouki Sato as part of MIT Geometry and Topology Seminar\n\n\nAbstract\nNote
  the time change!\n\nWe introduce a family of real-valued homology cobordi
 sm invariants r_s(Y) of oriented homology 3-spheres. The invariants r_s(Y)
  are based on a quantitative construction of filtered instanton Floer homo
 logy. Using our invariants\, we give several new constraints of the set of
  smooth boundings of homology 3-spheres. As one of the corollaries\, we gi
 ve infinitely many homology 3-spheres which cannot bound any definite 4-ma
 nifold. As another corollary\, we show that if the 1-surgery of a knot has
  negative Froyshov invariant\, then the 1/n-surgeries (n>0) of the knot ar
 e linearly independent in the homology cobordism group. This is a joint wo
 rk with Yuta Nozaki and Masaki Taniguchi.\n
LOCATION:https://researchseminars.org/talk/mitgt/8/
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