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Events happening on April 30, 2019

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Apr. 30, 2019 10am (MATH 350)	Geometry/Analysis Elaine Cozzi (Oregon State University) X Because pressure is determined globally for the incompressible Euler equations, a localized change to the initial velocity will have an immediate effect throughout space. For solutions to be physically meaningful, one would expect such effects to decrease with distance from the localized change, giving the solutions a type of stability. One can easily show that this is the case for sufficiently smooth solutions having spatial decay. In this talk, we consider a broader class of weak solutions with vorticity lacking spatial decay, and we show that such stability still holds. This is based on joint work with James Kelliher. Incompressible Euler equations and the effect of changes at a distance Sponsored by the Meyer Fund
Apr. 30, 2019 11am (MATH 350)	Number Theory Clayton Petsche (Oregon State University) X I will describe a certain two-parameter family of automorphisms of the p-adic affine plane. Each of these automorphisms admits a chaotic attractor, with non-integral Hausdorff dimension, on which it is topologically conjugate to a full two-sided shift map. The attractor supports a unit Borel measure which describes the distribution of the forward orbit of Haar-almost all points in the basin of attraction; this measure is a p-adic analogue of the SRB measures in smooth dynamics. Attractors associated to a family of hyperbolic p-adic plane automorphisms
Apr. 30, 2019 12:10pm (MATH …	Kempner Anton Dzhamay (University of Northern Colorado) X Many interesting examples of discrete integrable systems can be studied from the geometric point of view. In this talk we will consider two classes of examples of such system: autonomous (QRT maps) and non-autonomous (discrete Painlevé equations). We introduce some geometric tools to study these systems, such as the blowup procedure to construct algebraic surfaces on which the mappings are regularized, linearization of the mapping on the Picard lattice of the surface and, for discrete Painlevé equations, the decomposition of the Picard lattice into complementary pairs of the surface and symmetry sub-lattices and construction of a birational representation of affine Weyl symmetry groups that gives a complete algebraic description of our non-linear dynamic. We also will describe some examples of applications. Geometry of Discrete Integrable Systems: QRT Maps and Discrete Painlevé Equations
Apr. 30, 2019 2pm (MATH 220)	Agnes Szendrei (CU Boulder) Flexible Ultrafilters and the Theory of the Random Graph, Part 3
Apr. 30, 2019 2pm (MATH 350)	Lie Theory Shawn Burkett (Kent State) X Given a normal subgroup $N$ of a finite group $G$ , we define the subgroup $V(G∣ N)$ to be the product of the vanishing-off subgroups of all irreducible characters of $G$ not containing $N$ in their kernel. The map $N↦V(G∣ N)$ gives an order-preserving, join-preserving map from the lattice of normal subgroups of $G$ to itself. Thus there is right adjoint $N↦U(G∣ N)$ so that these two maps give a Galois connection on the lattice of normal subgroups of $G$ . In this talk we will explore the properties of the subgroups $U(G∣ N)$ , with special attention given to the subgroup $U(G)=U(G∣ Z(G))$ , which is the largest normal subgroup $U$ of $G$ for which every character in $Irr(G∣ U)$ vanishes off of $Z(G)$ . We will discuss groups satisfying $U(G)>1$ , and see that these are essentially $p$ -groups. Of particular interest will be nested generalized vanishing center (nested GVZ) groups --- finite groups satisfying the following two properties: $•$ (nested) The centers of the irreducible characters form a chain; $•$ (GVZ) Every irreducible character vanishes off of its center. We will use the vanishing-off subgroups and their adjoints to construct central series that will be used to give new characterizations of nested GVZ groups. This is joint work with Mark L. Lewis (Kent State University). Characterizations of nested GVZ groups in terms of vanishing-off subgroups of characters Sponsored by the Meyer Fund
Apr. 30, 2019 3pm (MATH 350)	Algebraic Geometry Yuchen Liu (Yale University) X We prove the K-moduli space of cubic threefolds is identical to their GIT moduli. More precisely, the K-(semi,poly)-stability of cubic threefolds coincide to the corresponding GIT stabilities, which could be explicitly calculated. In particular, this implies that all smooth cubic threefolds admit Kähler-Einstein metric as well as provides a precise list of singular KE ones. To achieve this, our main new contribution is an estimate in dimension three of the volumes of kawamata log terminal singularities introduced by Chi Li. This is joint work with Chenyang Xu. K-stability of cubic threefolds Sponsored by the Meyer Fund
Apr. 30, 2019 4pm (MATH 350)	Topology Katharine Adamyk (CU Boulder) Madsen Tillman Spectra

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