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SUMMARY:Roots and logs in the enumerative forest
DTSTART:20230427T131500
DTEND:20230427T150000
DTSTAMP:20260407T230643Z
UID:cd5c94c6eddd48508ace62c899d67b5bd20fc1cd5766632ad596c13b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Navid Nabijou\, Queen Mary University of London\nLogarithmic a
 nd orbifold structures provide two paths to the enumeration of curves with
  fixed tangencies to a normal crossings divisor. Simple examples demonstra
 te that the resulting systems of invariants differ\, but a more structural
  explanation of this defect has remained elusive. I will discuss joint wor
 k with Luca Battistella and Dhruv Ranganathan\, in which we identify birat
 ional invariance as the key property distinguishing the two theories. The 
 logarithmic theory is stable under strata blowups of the target\, while th
 e orbifold theory is not. By identifying a suitable system of “slope-sen
 sitive” blowups\, we define a limit orbifold theory and prove that it co
 incides with the logarithmic theory. Our proof hinges on a technique – r
 ank reduction – for reducing questions about normal crossings divisors t
 o questions about smooth divisors\, where the situation is much-better und
 erstood.\n 
LOCATION:MA A3 30 https://plan.epfl.ch/?room==MA%20A3%2030
STATUS:CONFIRMED
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