Department of Mathematics,
University of California San Diego

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Enumerative Geometry Seminar

Andrea Ricolfi
SISSA

Higher rank K-theoretic Donaldson-Thomas theory of points

Abstract:

Recently Okounkov proved Nekrasovs conjecture expressing the
partition function of K-theoretic DT invariants of the Hilbert scheme of
points Hilb($\mathbb C^3$, points) on affine 3-space as an explicit
plethystic exponential. We generalise Nekrasovs formula to higher rank,
where the Quot scheme of finite length quotients of the trivial rank $r$
bundle replaces Hilb($\mathbb C^3$,points). This proves a conjecture of
Awata-Kanno. Specialising to cohomological invariants, we obtain the
statement of Szabos conjecture. We discuss some further applications if
time permits. This is joint work with Nadir Fasola and Sergej Monavari.

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Zoom (contact host for zoom link)

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Department of Mathematics,
University of California San Diego

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Math 209 - Number Theory Seminar

Jishnu Ray
University of British Columbia

Conjectures in Iwasawa Theory of Selmer groups and Iwasawa Algebras

Abstract:

The Iwasawa Theory of Selmer groups provides a natural way for p-adic approach to the celebrated Birch and Swinnerton Dyer conjecture. Over a non-commutative p-adic Lie extension, the (dual) Selmer group becomes a module over a non-commutative Iwasawa algebra and its structure can be understood by analyzing ``(left) reflexive ideals'' in the Iwasawa algebra. In this talk, we will start by recalling several existing conjectures in Iwasawa Theory and then we will give an explicit ring-theoretic presentation, by generators and relations, of such Iwasawa algebras and sketch its implications in understanding the (two-sides) reflexive ideals. Generalizing Clozel's work for $SL(2)$, we will also show that such an explicit presentation of Iwasawa algebras can be obtained for a much wider class of p-adic Lie groups viz. uniform pro-p groups and the pro-p Iwahori of $GL(n,Z_p)$. Further, if time permits, I will also sketch some of my recent Iwasawa theoretic results joint with Sujatha Ramdorai.

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Department of Mathematics,
University of California San Diego

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Math 208 - Algebraic Geometry

Gavril Farkas
Humbolt Universit"at, Berlin

Green's Conjecture via Koszul modules.

Abstract:

Using ideas from geometric group theory we provide a novel approach to Green's Conjecture on syzygies of canonical curves. Via a strong vanishing result for Koszul modules we deduce that a general canonical curve of genus $g$ satisfies Green's Conjecture when the characteristic is zero or at least $(g+2)/2$. Our results are new in positive characteristic (and answer positively a conjecture of Eisenbud and Schreyer), whereas in characteristic zero they provide a different proof for theorems first obtained in two landmark papers by Voisin. Joint work with Aprodu, Papadima, Raicu and Weyman.

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Contact Prof J. McKernan for the Zoom URL

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