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Pure Math Graduate Student Seminar: Ashley Tharp, NC State, Arcs and shards

SAS 2235

The group of permutations is the canonical example of a finite Coxeter group, and each permutation can be represented visually by a noncrossing arc diagram. Each diagram encodes the canonical join representation of its permutation, and diagrams can be used to understand lattice congruences on the weak order of type A, equivalence relations that respect the…

Pure Math Graduate Student Seminar: Kylan Schatz, NC State, Abelian 3-cocycles from Quadratic Forms – Quinn’s Formula

SAS 2235

For some nice subclass of braided monoidal categories, the associator and braiding data are described by an Abelian 3-cocycle . Eilenberg and MacLane demonstrated a surprisingly simple isomorphism between the groups of Abelian 3-cocycles with coefficients in  and quadratic forms with coefficients in , the trace map  by . Like many category theoretical results, this was proven at the level of…

Pure Math Graduate Student Seminar: Reeshad Arian, NC State, RT invariance of 3 manifolds

SAS 2235

Ed Witten's papers in 1988 drew out the connection between Jones Polynomials of Knots and Chern-Simons theory of 3-dimensional TQFT. Following his work, Reshetikhin and Turaev formulated invariants of 3-manifolds via colored framed knots leading to new TQFTs. In this talk, I will introduce Dehn Surgery on knots, framed knots colored with representations of Hopf…

Pure Math Graduate Student Seminar: Jack Reever, NC State, Isothermic Surfaces and Bonnet Pairs: How Are They Defined? Do They Have Special Properties? Let’s Find Out!

SAS 2235

In this talk, we begin by introducing the audience to some fundamentals of differential geometry of surfaces in ℝ3, focusing on curvature and the adequately named first and second fundamental forms. We will discuss what special parameterizations and properties give rise to isothermic surfaces. Equipped with these tools, we will look at the fundamental theorem for surfaces,…

Pure Math Graduate Student Seminar: Francisco Ponce Carrion, Marginal Independence Models

SAS 2235

Marginal independence models have been commonly studied in the context of graphical models, where we use a graph to convey the different marginal independence relations between random variables. However, there are marginal independence relations that cannot be expressed with a graph, which is why we provide a more general framework in which we can define…

Pure Math Graduate Student Seminar: Reeshad Arian, Geometry over \mathbb{F}_1

SAS 2102

Even though the field with one element, , is a meaningless concept, shadows of it have been apparent in multiple categorical analogies. More immediately, one can generalize multiple constructions from algebraic geometry over  to general commutative monoids, which behave like rings over this elusive . In this talk we define, via this analogy, schemes over , and consider zeta…

Pure Math Graduate Student Seminar: Jack Reever, A 2-parameter family of helicoidal surfaces

SAS 2102

Of course, anybody can deform a surface in whatever way they want. However, is there a way to deform a surface of revolution into a helicoid while preserving an isometry? How many ways are there? All these questions and more will be answered on Monday, February 13. Zoom Meeting link:  https://ncsu.zoom.us/j/92762214990?pwd=MnA1TnNVQUpzUlo3cTM5RmlNWVF4Zz09      Password: noodle

Pure Math Graduate Student Math Seminar: Andrew Shedlock, A smooth two Parameter Family of Geodesically Equivalent Metrics

SAS 2102

In Riemannian geometry, given a Riemannian manifold (M,g) one can use geodesics associated with (M,g) to determine information about the shortest distance between points, curvature, triangles on a manifold and Euler characteristic of the space of M in special cases. Thankfully, given a metric on a manifold, we can always determine geodesics on said manifold.…

Pure Math Graduate Student Seminar: Daniel Profili, NC State, Eigenvalue configurations for real symmetric matrices

SAS 2102

Real symmetric matrices appear in a wide range of disciplines. One geometric problem that can be asked of two real symmetric matrices is: how are their eigenvalues arranged on the real line? Can we characterize all matrices whose eigenvalues realize a certain arrangement? In this talk, we will use principles from basic algebraic geometry and…

Pure Math Graduate Student Seminar: Kylan Schatz, NC State, Fusion Rules for G-crossed Extensions of Modular Categories

SAS 2102

Determining the fusion coefficients for an abstract fusion category is very difficult, and generalizes the problem of plethysm for group representations. As is the case in finite groups, restricting the class of objects we consider can help us to obtain better general results. When one has a group acting on a modular category, it is possible to…

Pure Math Graduate Student Seminar: Alex Betz, NC State, Module Categories and Algebra Objects

SAS 2102

 When studying Tensor Categories we want to understand what algebra objects can be found in those categories. After finding such objects it's natural to consider their A -modules and more importantly the category of A (bi)-modules. This talk will attempt to explain this concept and enlighten listeners with motivating examples. Zoom Meeting link:  https://ncsu.zoom.us/j/92762214990?pwd=MnA1TnNVQUpzUlo3cTM5RmlNWVF4Zz09      Password:…

Pure Math Graduate Student Seminar: Tim Ablondi, Koszul Duality in a Hypertoric Setting

SAS 2102

Hypertoric varieties are quaternionic analogs of toric varieties, important for their interaction with the combinatorics of matroids as well as for their prominent place in the rapidly expanding field of algebraic symplectic and hyperkahler geometry.  In the last decade, hypertoric varieties have appeared prominently in investigations of symplectic duality, a mathematical incarnation of 3d mirror…

Pure Math Graduate Student Seminar: Ian Klein, NC State, The Chromatic Symmetric Function and the Stanley-Stembridge Conjecture

SAS 2102

Symmetric functions are very interesting combinatorial objects. After decomposing certain symmetric functions in terms of different bases, we can often combinatorially interpret the resulting coefficients. This is made particularly easy if those coefficients are positive (or controllably negative). The chromatic symmetric function is one such symmetric function, and its decomposition has been of interest for…

Pure Math Graduate Student Seminar: Jack Reever, The journey to finding an explicit solution to a cross-ratio system

SAS 2106

Integrable cross-ratio maps are solutions to one of the discrete integrable equations on quad-graphs. These maps may be of interest to many mathematicians; just to name a few uses, discrete holomorphic functions, orthogonal circle packings, and polygon recutting are all special cases of integrable cross-ratio maps. The goal of my research is to find an…

Pure Math Graduate Student Seminar: Reeshad Arian, NC State, Quandles and Knots

SAS 2106

A fundamental problem in knot theory is determining when two distinct knot diagrams represent the same knot. This is traditionally addressed through the use of invariants such as the knot group, Alexander polynomial, and Jones polynomial, among others. While the knot group distinguishes prime knots, it is known to be incomplete as a knot invariant.…

Pure Math Graduate Student Seminar: Everett Meike, NC State, Cataloguing 2-adjacent knots

SAS 2106

Generalizing unknotting number, n-adjacent knots have n crossings such that changing any non-empty subset of them results in the unknot. We determine the 2-adjacent knots through 12-crossings, with one exception. Using Heegaard Floer d-invariants and the Alexander polynomial, we develop a new technique to obstruct 2-adjacency, and we prove conjectures of Ito and Kato regarding…

Pure Math Graduate Student Seminar: Tim Ablondi, Investigating the $\widetilde{B}(V)$ Algebra From Hypertoric Geometry

SAS 2106

This talk will begin by constructing a new algebra based on a generalization of the set of relations for Ozsváth-Szabó's bordered Heegaard Floer algebra $B(n,k)$. Then, I will strengthen an existing result by establishing an isomorphism between our new algebra and the algebra $\widetilde{B}(\mathcal{V})$ associated with an arrangement of real affine hyperplanes. If time permits, I’ll…