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DTSTART:20260308T070000
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DTSTART:20251102T060000
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DTSTART;TZID=America/Toronto:20260527T153000
SEQUENCE:0
TRANSP:TRANSPARENT
DTEND;TZID=America/Toronto:20260527T170000
URL:https://uwaterloo.ca/pure-mathematics/events/differential-geometry-work
 ing-seminar-191
SUMMARY:Differential Geometry Working Seminar
CLASS:PUBLIC
DESCRIPTION:VIKTOR MAJEWSKI\, UNIVERSITY OF WATERLOO\n\n_Obstructions to Sm
 ooth Full Holonomy Cayley Fibrations_\n\nWe study smooth fibrations of com
 pact torsion-free\n$\\textrm{Spin}(7)$-manifolds by Cayley submanifolds.Us
 ing geometric\nand topological constraints coming from the\n$\\textrm{Spin
 }(7)$-structure\, we show that only two topological\nconfigurations can ar
 ise. One of these is excluded by a spinnability\ncriterion for fiber bundl
 es\,with the relevant hypothesis verified\nusing gauge-theoretic input\, w
 hile the remaining case is reduced to an\nopen conjecture in $4$-manifold 
 topology. In particular\, this rules\nout smooth Cayley fibrations on all 
 known examples of compact\ntorsion-free $\\textrm{Spin}(7)$-manifolds.\n\n
 MC 5417
DTSTAMP:20260605T002834Z
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