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SUMMARY:Alexandra Kjuchukova (Notre Dame)
DTSTART:20210629T140000Z
DTEND:20210629T151500Z
DTSTAMP:20260423T024724Z
UID:rlgts/33
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/rlgts/33/">C
 overs of S^3 bounding covers of B^4</a>\nby Alexandra Kjuchukova (Notre Da
 me) as part of Regensburg low-dimensional geometry and topology seminar\n\
 n\nAbstract\nLet $G$ be a group\, $K$ a knot and $\\rho$ a surjective homo
 morphism $\\pi_1(S^3 \\backslash K) \\to G$. When does a branched cover of
  $S^3$ determined by $\\rho$ extend over $B^4$\, with a smooth branching l
 ocus $F$? Previously\, the answer was only known under quite strong assump
 tions\, e.g. when K is slice and G a dihedral group. I will define a new i
 nvariant which detects the existence of such an extension for all knots an
 d all metabelian groups. I will give examples of computing the obstruction
  and constructing the desired surface $F$. Joint work with Kent Orr.\n
LOCATION:https://researchseminars.org/talk/rlgts/33/
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