MAGA16

Meeting on Algebraic Geometry for Applications

Clemson University

April 9, 2016 (Saturday)

 

This is a small (local) conference which goal is to bring together researchers and their students who are using algebraic geometry.
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[tab_item title=”SPEAKERS AND SCHEDULE”]

Speakers

 

 

Schedule

Location: Matin Hall M first floor, Department of Mathematical Sciences
Time Talk
8:45 – 9:00 Registration and welcome message
9:00 – 9:45 [toggle_box]
[toggle_item title=”Sebastian Pokutta – A polyhedral characterization of border bases” active=”false”]
Border bases arise as a canonical generalization of Groebner bases. We provide a polyhedral characterization of all order ideals (and hence border bases) that are supported by a zero-dimensional ideal: order ideals that support a border basis correspond one-to-one to integral points of the order ideal polytope. In particular, we establish a crucial connection between the ideal and its combinatorial structure. Based on this characterization we adapt the classical border basis algorithm to allow for computing border bases for arbitrary order ideals, which are independent of term orderings. We also show that finding a maximum weight order ideal that supports a border basis is NP-hard, and that the convex hull of admissible order ideals has no polynomial polyhedral description.
(joined work with Gábor Braun)[/toggle_item]
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9:55 – 10:40 [toggle_box]
[toggle_item title=”Daniel Bernstein – Toric Varieties in Statistics” active=”false”]
In the first half of my talk, I will explain how certain statistical models can be viewed as toric varieties, and how the algebraic theory can be leveraged to develop algorithms for hypothesis testing. In the second half, I will describe some “niceness” properties that a toric ideal can satisfy, and their implications for statistical algorithms. Then, I will present some recent results and work in progress related to these properties for hierarchical models. This is joint work with Seth Sullivant.[/toggle_item]
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10:40 – 11:00 Break
11:00 – 11:45 [toggle_box]
[toggle_item title=”Timo de Wolff – New Certificates for Nonnegativity via Circuit Polynomials and Geometric Programming” active=”false”]
Deciding nonnegativity of real polynomials is a key question in real algebraic geometry with crucial importance in polynomial optimization. Since this problem is NP-hard, one is interested in finding sufficient conditions (certificates) for nonnegativity, which are easier to check. Since the 19th century the standard certificates are sums of squares (SOS); see particularly Hilbert’s 17th problem.
In this talk, we introduce polynomials supported on circuits. For this class nonnegativity is characterized by an invariant, which can be derived from the initial polynomial immediately. In consequence, we obtain an entirely new class of nonnegativity certificates, which are independent of SOS certificates.
Our certificates crucially extend geometric programming approaches for the computation of lower bounds in polynomial optimization. Particularly, for polynomials with simplex Newton polytope our approach is significantly faster and often yields better than bounds than semidefinite programming, which is the standard method for polynomial optimization.
These results generalize earlier works by Fidalgo, Ghasemi, Kovacec, Marshall, and Reznick. The talk is based on joint work with Sadik Iliman.[/toggle_item]
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11:45 – 2:00 Lunch break
2:00 – 2:45 [toggle_box]
[toggle_item title=”Elena Dimitrova – Properties and applications of vanishing ideals of points over finite fields” active=”false”]
The easiest geometric object to compute over affine or projective space is a single point. It has no secrets — in particular, its defining ideal, the set of polynomials which vanish at the point, is straightforward to describe. In contrast, vanishing ideals of multiple points is a challenge even over a finite field. Though efficient techniques for computing them, such as the BM-algorithm, exist, for most sets of points the vanishing ideal has several equally “nice” generating sets which yield multiple interpolating polynomials. In this talk, we will explore properties of vanishing ideals, particularly over finite fields. Additionally, we will see how these questions arise naturally in the design of experiments and selection of algebraic models of systems in mathematical biology.
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2:55 – 3:40 [toggle_box]
[toggle_item title=”Brent Davis – Quartet Cleaning using the Nearest Statistical Model of Evolution” active=”false”]

Research has shown that the accuracy of many quartet-based phylogenetic supertree
reconstruction algorithms are sensitive to input error. Using a combination of  optimization,
numerical algebraic geometry (NAG), and statistical hypothesis testing we propose a
quartet-based reconstruction algorithm called the nearest model method. This method
selects the best fit quartet tree given an aligned nucleotide sequence. The goal of this method
is to assist supertree algorithms by minimizing errors caused from incorrectly inferred trees.
Using NAG methods, performance of the nearest model method using data generated from the
Jukes Cantor model of evolution is discussed. We also discuss the performance of the nearest
model method using the interior-point method on a variety of data and models of evolution.

(joined work with Emily Castner and Joseph Rusinko)[/toggle_item]
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3:40 – 4:00 Break
4:00 – 4:45 [toggle_box]
[toggle_item title=”Joshua Hallam – Combinatorial Hopf Algebras and Symmetric Functions” active=”false”]
Hopf algebras arose in the study of algebraic topology during the 1940’s. They have since been found to be extremely useful in many other disciplines, including combinatorics. In this talk we will consider a few examples of Hopf algebras that arise in combinatorics. We will see a very nice relationship between these Hopf algebras and symmetric functions. Moreover, we will see how combinatorial properties can be seen as consequences of algebraic properties of Hopf algebras. No prior knowledge of Hopf algebras or symmetric functions will be assumed.
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4:55 – 5:40 [toggle_box]
[toggle_item title=”Alex Kasman – Spectral Curves and the Sato Grassmannian: Algebraic Geometry for Integrable Nonlinear PDEs” active=”false”]
The analysis of partial differential equations does not usually involve any advanced algebraic geometry. However, in the late 20th century it was discovered that a certain class of nonlinear PDEs having particle-like solutions called “solitons” also has a rich algebro-geometric structure. Vector bundles over complex projective curves and Grassmannian varieties can be used to produce and understand the solutions to these special but important differential equations. This talk will quickly review the history of this subject, present some of the key results, and also “advertise” a few of my own contributions to this surprising interface between algebraic geometry and mathematical physics.[/toggle_item]
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6:30 Optional dinner (registration on site)

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[tab_item title=”LIST OF PARTICIPANTS”]

First Name Last Name Institution
Travis Baumbaugh Clemson University
Daniel Bernstein North Carolina State University
Michael Burr Clemson University
Benjamin Case Clemson University
Brent Davis Colorado State University
Timo de Wolff Texas A&M University
Elena Dimitrova Clemson University
Gabriel John Dusing University of Tennessee – Knoxville
Michael Eldredge Clemson University
Shuhong Gao Clemson University
Luke Giberson Clemson University
Brandon Goodell Clemson University
Akshay Gupte Clemson University
Josh Hallam Wake Forest University
Cvetelina Hill Georgia Institute of Technology
Alex Kasman College of Charleston
Kisun Lee Georgia Tech
Drew Lipman Clemson University
Felice Manganiello Clemson University
Gretchen Matthews Clemson University
Sebastian Pokutta Georgia Tech
Svetlana Poznanovic Clemson University
Sean Sather-Wagstaff Clemson University
Josephine Yu Georgia Tech

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[tab_item title=”LODGING AND PARKING”]

Lodging options in Clemson:
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Parking:

Parking enforcement will exercise relaxed enforcement in the following areas from 8:00 am – 6:00 pm on April 9: E-6, Parkway Dr. and Calhoun Dr.
 (E-6 is the best option being it the parking area closest to the Department.)
Relaxed enforcement means that a guest parked in a valid parking space will not receive a citation for not having a permit. Guest parking in a metered parking space are expected to pay the meter as regulations are enforced seven days a week from 7:00 am – 10:00 pm.

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Map:

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Organizers: Michael Burr — Felice Manganiello — Svetlana Poznanović
MAGA is partially supported by a grant from the Simons Foundation (#282399 to Michael Burr) and NSF: CCF-1527193