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SUMMARY:Lee Kennard (Syracuse University)
DTSTART:20200506T150000Z
DTEND:20200506T160000Z
DTSTAMP:20260423T035708Z
UID:VSGS/2
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/VSGS/2/">Tor
 us actions and positive curvature</a>\nby Lee Kennard (Syracuse University
 ) as part of Virtual seminar on geometry with symmetries\n\n\nAbstract\nIn
  the 1930s\, H. Hopf conjectured that an even-dimensional Riemannian manif
 old with positive sectional curvature has positive Euler characteristic. I
 n joint work with M. Wiemeler and B. Wilking\, this is confirmed in the sp
 ecial case where the isometry group has rank at least five. Previous resul
 ts of this form required the rank to grow to infinity as a function of the
  manifold dimension. The main new tool is a structural result for represen
 tations of tori with the special property that all isotropy groups are con
 nected. Such representations are surprisingly rigid\, and we analyze them 
 using only elementary techniques.\n
LOCATION:https://researchseminars.org/talk/VSGS/2/
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