Seminar Calendar
for Algebra, Geometry and Combinatorics events the next 12 months of Sunday, January 1, 2017.

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Questions regarding events or the calendar should be directed to Tori Corkery.
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              1  2  3    1  2  3  4  5  6  7             1  2  3  4
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Thursday, January 19, 2017

Algebra, Geometry and Combinatorics
3:00 pm   in 347 Altgeld Hall,  Thursday, January 19, 2017
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Submitted by lescobar.
Balazs Elek (Cornell University)
Pizzas and Toric surfaces with Kazhdan-Lusztig atlases
Abstract: A Bruhat atlas, introduced by He, Knutson and Lu, on a stratified variety is a way of modeling the stratification locally on the stratification of Schubert cells by opposite Schubert varieties. They described Bruhat atlases on many interesting varieties, including partial flag varieties and on wonderful compactifications of groups. We will discuss some results toward a classification of varieties with Bruhat atlases, focusing on the 2-dimensional toric case. In this case, the answer may be stated in terms of the moment polygon of the toric surface, which one should first slice up, then put toppings on, much like one would do while preparing a pizza.

Thursday, February 16, 2017

Algebra, Geometry and Combinatorics Seminar
3:00 pm   in 347 Altgeld Hall,  Thursday, February 16, 2017
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Submitted by lescobar.
Cara Monical (UIUC)
Set-Valued Skylines
Abstract: Set-valued tableaux play an important role in combinatorial $K$-theory. Separately, semistandard skyline fillings are a combinatorial model for Demazure atoms and key polynomials. We unify these two concepts by defining a set-valued extension of semistandard skyline fillings and then give analogues of results of J. Haglund, K. Luoto, S. Mason, and S. van Willigenberg.

Thursday, February 23, 2017

Algebra, Geometry and Combinatorics Seminar
3:00 pm   in 347 Altgeld Hall,  Thursday, February 23, 2017
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Submitted by lescobar.
Bennet Goeckner (The University of Kansas)
A non-partitionable Cohen-Macaulay complex
Abstract: Stanley conjectured in 1979 that all Cohen-Macaulay complexes were partitionable. We will construct an explicit counterexample to this conjecture, which also disproves a related conjecture about the Stanley depth of monomial ideals. This talk is based on joint work with Art Duval, Caroline Klivans, and Jeremy Martin. No prerequisite knowledge of simplicial complexes or commutative algebra will be assumed.

Friday, March 3, 2017

Algebra, Geometry and Combinatorics Seminar
1:00 pm   in 347 Altgeld Hall,  Friday, March 3, 2017
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Submitted by lescobar.
Bernd Schober (University of Toronto)
Embedded resolution of singularities in dimension two
Abstract: When studying a singular variety one aims to find a variety that shares many properties with the original one, but that is easier to handle. One way to obtain this is via resolution of singularities. In contrast to the quite well understood situation over fields of characteristic zero, only little is known in positive or mixed characteristic and resolution of singularities remains still an important open problem. One of the key ideas over fields of characteristic zero is the notion of maximal contact. After briefly explaining its power, I will point out problems that arise in positive characteristic. Then I will focus on the known two-dimensional case and will discuss the resolution algorithm constructed by Cossart, Jannsen and Saito. Finally, I will explain how polyhedra can be used to detect the improvement of the singularity along the process. This is joint work with Vincent Cossart.