Week of January 7, 2024

Mon Jan 8, 2024
4:00pm to 5:00pm - RH 306 - Applied and Computational Mathematics
Sean Lawley - (University of Utah)
Stochastics in medicine: Delaying menopause and missing drug doses

Stochastic modeling and analysis can help answer pressing medical questions. In this talk, I will attempt to justify this claim by describing recent work on two problems in medicine. The first problem concerns ovarian tissue cryopreservation, which is a proven tool to preserve ovarian follicles prior to gonadotoxic treatments. Can this procedure be applied to healthy women to delay or eliminate menopause? How can it be optimized? The second problem concerns medication nonadherence. What should you do if you miss a dose of medication? How can physicians design dosing regimens that are robust to missed/late doses? I will describe (a) how stochastics theory offers insights into these questions and (b) the mathematical questions that emerge from this investigation.

4:00pm to 5:00pm - NS2 1201 - Distinguished Lectures
Jon Keating - (Oxford University)
Joint Moments (Seminar)

I will discuss recent progress concerning the joint moments of the characteristic polynomial of a random unitary matrix and its derivates, in the context of the connection between the Riemann zeta-function and random matrix theory.

Tue Jan 9, 2024
4:00pm to 5:00pm - RH 306 - Differential Geometry
Laura Fredrickson - (University of Oregon)
TBA

Cancelled.

4:00pm to 5:00pm - NS2 1201 - Differential Geometry
Jon Keating - (Oxford)
TBA
4:00pm to 5:00pm - NS2 1201 - Distinguished Lectures
Jon Keating - (Oxford University)
Random matrices and the Riemann zeta-function (Colloquium)

I will review connections between random matrix theory and statistical properties of the Riemann zeta-function, including recent developments relating to extreme values of the zeta function on the critical line.

Wed Jan 10, 2024
2:00pm to 3:00pm - NS 1201 - Special Colloquium
Congling Qiu - (MIT)
Modified diagonal and symmetry of a curve

The modified diagonal on the triple product of a curve was first introduced by Gross and Schoen in the 90’s. This simply defined object holds fundamental importance in the study of the geometry and arithmetic of curves. One basic question is whether the modified diagonal vanishes under “deformation”. I will introduce the origin of this type of question and provide a brief history of the study of the modified diagonal. Subsequently, I will discuss my collaborative works with W. Zhang, where we demonstrated that such vanishing can be dictated by the symmetry of the curve. As an application in number theory, we proved a case of the notorious Beilinson—Bloch conjecture, a generalization of the Millennium Birch—Swinnerton-Dyer conjecture. Finally, I want to propose some new questions.

 

Thu Jan 11, 2024
2:00pm to 3:00pm - NS 1201 - Special Colloquium
Be'eri Greenfeld - (U Washington)
Quantifying Infinitude in Algebraic Structures: Growth, Local Smallness, and Global Largeness

The growth of an infinite-dimensional algebra is a fundamental tool to measure its "size." The growth of noncommutative algebras plays an important role in noncommutative geometry, representation theory, differential algebraic geometry, symbolic dynamics, homological stability results, and more. 

We analyze the space of growth functions of algebras, answering a question of Zelmanov on the existence of certain 'holes' in this space, and provide evidence for the ampleness of the possible growth rates of algebras with prescribed properties; we conclude a strong quantitative solution of the Kurosh Problem on algebraic algebras.

Utilizing new layers of the interplay between noncommutative algebra and symbolic dynamics, we exhibit surprising pathologies in the prime spectrum and tensor product structure of algebras with polynomial growth, thereby providing counterexamples to questions of Bergman, Krause, Lenagan, and others; applying our methods to algebras of faster growth types, we resolve a conjecture of Bartholdi on amenable representations in exponential growth.

Finally, the largest objects (groups, algebras, Lie algebras) are, in many contexts, those containing free substructures. We discuss the coexistence of this phenomenon with finiteness properties -- in particular, "almost algebraicity" of algebras and "almost periodicity" of groups -- from algebraic, geometric, and probabilistic perspectives.

This talk is partially based on joint works with Bell, Goffer, and Zelmanov.

3:00pm to 4:00pm - RH 510R - Applied and Computational Mathematics
Eun-Jae Park - (Yonsei University)
Adaptive multi-level algorithm for a class of nonlinear problems

In this talk, we first develop and analyze two-grid/multi-level algorithms via mesh refinement in the abstract framework of Brezzi, Rappaz, and Raviart for approximation of branches of
nonsingular solutions. Optimal fine grid accuracy of two-grid/multi-level algorithms can be achieved via the proper scaling of relevant meshes. An important aspect of the proposed
algorithm is the use of mesh refinement in conjunction with Newton-type methods for system solution in contrast to Newton's method on a fixed mesh. 

 

Then, we propose an adaptive mesh-refining based on the multi-level algorithm and derive a unified a posteriori error estimate for a class of nonlinear problems. We have shown that the multi-level
algorithm on adaptive meshes retains quadratic convergence of Newton's method across different mesh levels, which is numerically validated. Our framework facilitates to use the general theory established
for a linear problem associated with given nonlinear equations. In particular, existing a posteriori error estimates for the linear problem can be utilized to find reliable error estimators for the given nonlinear
problem.

 

As applications of our theory, we consider the pseudostress-velocity formulation of Navier-Stokes equations and the standard Galerkin formulation of semilinear elliptic equations. Reliable and efficient a
posteriori error estimators for both approximations are derived. Finally, several numerical examples are presented to test the performance of the algorithm and validity of the theory developed.

 

Reference:

 

1. Dongho Kim, Eun-Jae Park, Boyoon Seo, A unified framework for two-grid methods for a class of nonlinear problems, Calcolo, December 2018, 55:45

2. Dongho Kim, Eun-Jae Park, Boyoon Seo, Optimal Error Estimates for the Pseudostress Formulation of the Navier-Stokes Equations, Applied Mathematics Letters, Volume 78, April 2018, pp 24-30

3. Dongho Kim, Eun-Jae Park, Boyoon Seo,  Convergence of Multi-level Algorithms for a Class of Nonlinear Problems. J. Sci. Comput. 84 (2020), no. 2, Paper No. 34, 23 pp.

4. Dongho Kim, Eun-Jae Park, Boyoon Seo,  Adaptive Multi-level Algorithms for a Class of Nonlinear Problems,  Invited paper in Comput. Meth. Appl. Math. 

 

 

Fri Jan 12, 2024
2:00pm to 3:00pm - NS 1201 - Special Colloquium
Ravi Shankar - (Princeton)
Doubling method for Monge-Ampere and special Lagrangian type equations

We present a new, recent doubling method for establishing a priori estimates, then classical solvability and regularity for solutions to fully nonlinear PDEs.  The method produces the missing estimates for the quadratic Hessian and prescribed hypersurface scalar curvature PDEs in dimension four.  It also gives new proofs of the estimates and regularity for Monge–Ampère and special Lagrangian equations and provides prospects for classical solvability of alternative Dirichlet problems.