BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Claremont Center for the Mathematical Sciences - ECPv6.15.17.1//NONSGML v1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH X-WR-CALNAME:Claremont Center for the Mathematical Sciences X-ORIGINAL-URL:https://colleges.claremont.edu/ccms X-WR-CALDESC:Events for Claremont Center for the Mathematical Sciences REFRESH-INTERVAL;VALUE=DURATION:PT1H X-Robots-Tag:noindex X-PUBLISHED-TTL:PT1H BEGIN:VTIMEZONE TZID:America/Los_Angeles BEGIN:DAYLIGHT TZOFFSETFROM:-0800 TZOFFSETTO:-0700 TZNAME:PDT DTSTART:20200308T100000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0700 TZOFFSETTO:-0800 TZNAME:PST DTSTART:20201101T090000 END:STANDARD BEGIN:DAYLIGHT TZOFFSETFROM:-0800 TZOFFSETTO:-0700 TZNAME:PDT DTSTART:20210314T100000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0700 TZOFFSETTO:-0800 TZNAME:PST DTSTART:20211107T090000 END:STANDARD BEGIN:DAYLIGHT TZOFFSETFROM:-0800 TZOFFSETTO:-0700 TZNAME:PDT DTSTART:20220313T100000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0700 TZOFFSETTO:-0800 TZNAME:PST DTSTART:20221106T090000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210301T150000 DTEND;TZID=America/Los_Angeles:20210301T160000 DTSTAMP:20260415T141019 CREATED:20210112T180006Z LAST-MODIFIED:20210210T190755Z UID:2104-1614610800-1614614400@colleges.claremont.edu SUMMARY:Applied math. talk: Blowup rate estimates of a singular potential in the Landau-de Gennes theory for liquid crystals by Xiang Xu\, Old Dominion University. DESCRIPTION:Abstract: The Landau-de Gennes theory is a type of continuum theory that\ndescribes nematic liquid crystal configurations in the framework of the\nQ-tensor order parameter. In the free energy\, there is a singular bulk\npotential which is considered as a natural enforcement of a physical\nconstraint on the eigenvalues of symmetric\, traceless Q-tensors. In this\ntalk we shall discuss some analytic properties related to this singular\npotential. More specifically\, we provide precise estimates of both this\nsingular potential\nand its gradient as the Q-tensor approaches its physical boundary. URL:https://colleges.claremont.edu/ccms/event/applied-math-talk-by-xiang-xu-old-dominion-university/ LOCATION:Zoom meeting\, United States CATEGORIES:Applied Math Seminar END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210303T161500 DTEND;TZID=America/Los_Angeles:20210303T173000 DTSTAMP:20260415T141019 CREATED:20210204T003334Z LAST-MODIFIED:20210221T214207Z UID:2166-1614788100-1614792600@colleges.claremont.edu SUMMARY:Ioana Dumitriu DESCRIPTION:Title: Spectral gap in random regular graphs and hypergraphs \nAbstract: Random graphs and hypergraphs have been used for decades to model large-scale networks\, from biological\, to electrical\, and to social. Various random graphs (and their not-so-random properties) have been connected to algorithms solving problems from community detection to matrix completion\, coding theory\, and various other statistics / machine learning fundamental questions; in the past decade\, this research area has expanded to include random hypergraphs. One of these special properties is the spectral gap for graph-associated matrices; roughly speaking\, it means that the main eigenvalue(s) are well-separated from the bulk and it guarantees strong connectivity properties. This talk will take a look at the spectra of adjacency / Laplacian matrices for some random regular models\, explain how we know that the spectral gap is there\, and connect spectral properties to the aforementioned applications. It will cover joint work with Gerandy Brito\, Kameron Decker Harris\, and Yizhe Zhu. \nIoana Dumitriu is a Professor of Mathematics at The University of California\, San Diego. URL:https://colleges.claremont.edu/ccms/event/ioana-dumitru/ LOCATION:Zoom CATEGORIES:Colloquium ORGANIZER;CN="Helen Wong":MAILTO:hwong@cmc.edu END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210308T150000 DTEND;TZID=America/Los_Angeles:20210308T160000 DTSTAMP:20260415T141019 CREATED:20210112T180325Z LAST-MODIFIED:20210223T174630Z UID:2106-1615215600-1615219200@colleges.claremont.edu SUMMARY:Applied math. talk: Optimal control of the SIR model in the presence of transmission and treatment uncertainty by Henry Schellhorn\, CGU DESCRIPTION:Abstract \nThe COVID-19 pandemic illustrates the importance of treatment-related decision making in populations. This article considers the case where the transmission rate of the disease as well as the efficiency of treatments is subject to uncertainty. We consider two different regimes\, or submodels\, of the stochastic SIR model\, where the population consists of three groups: susceptible\, infected and recovered. In the first regime the proportion of infected is very low\, and the proportion of susceptible is very close to 100%.  This corresponds to a disease with few deaths and where recovered individuals do not acquire immunity. In a second regime\, the proportion of infected is moderate\, but not negligible. We show that the first regime corresponds almost exactly to a well-known problem in finance\, the problem of portfolio and consumption decisions under mean-reverting returns (Wachter\, JFQA 2002)\, for which the optimal control has an analytical solution. We develop a perturbative solution for the second problem. To our knowledge\, this paper represents one of the first attempts to develop analytical/perturbative solutions\, as opposed to numerical solutions to stochastic SIR models. URL:https://colleges.claremont.edu/ccms/event/applied-math-talk-optimal-control-of-the-sir-model-in-the-presence-of-transmission-and-treatment-uncertainty-by-henry-schellhorn-cgu/ LOCATION:Zoom meeting\, United States CATEGORIES:Applied Math Seminar END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210315T150000 DTEND;TZID=America/Los_Angeles:20210315T160000 DTSTAMP:20260415T141019 CREATED:20210114T012637Z LAST-MODIFIED:20210114T012637Z UID:2118-1615820400-1615824000@colleges.claremont.edu SUMMARY:Applied Math. Talk: by a guest University of UTAH DESCRIPTION:TBA URL:https://colleges.claremont.edu/ccms/event/applied-math-talk-by-a-guest-university-of-utah/ LOCATION:Zoom meeting\, United States CATEGORIES:Applied Math Seminar END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210317T161500 DTEND;TZID=America/Los_Angeles:20210317T173000 DTSTAMP:20260415T141019 CREATED:20210204T003526Z LAST-MODIFIED:20210312T000508Z UID:2168-1615997700-1616002200@colleges.claremont.edu SUMMARY:Finding soap films in non-Euclidean geometry (Prof. David Bachman) DESCRIPTION:Title: Finding soap films in non-Euclidean geometry \nAbstract: In many computer graphics applications we approximate a smooth surface with one made up of tiny triangles. A common problem is to determine which way to move the vertices (the corners of the triangles)\, so that the total surface area decreases. If the boundary of the surface remains fixed\, this allows us to find the soap film surface spanned by that boundary curve. In Euclidean geometry this leads to the famous “cotan-Laplace formula.” After reviewing this formula we will introduce spherical and hyperbolic space\, and discuss a solution to the same problem in those geometries. \nDr. Bachman is Professor of Mathematics at Pitzer College and Director of the Claremont Center for the Mathematical Sciences. URL:https://colleges.claremont.edu/ccms/event/david-bachman/ LOCATION:Zoom CATEGORIES:Colloquium ORGANIZER;CN="Helen Wong":MAILTO:hwong@cmc.edu END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210322T150000 DTEND;TZID=America/Los_Angeles:20210322T160000 DTSTAMP:20260415T141019 CREATED:20210112T180523Z LAST-MODIFIED:20210317T211201Z UID:2108-1616425200-1616428800@colleges.claremont.edu SUMMARY:Applied math. talk: Periodic travelling waves in nonlinear wave equations: modulation instability and rogue waves by Dmitry Pelinovsky\, McMaster University\, Canada DESCRIPTION:Abstract:     I will overview the following different wave phenomena in\nintegrable nonlinear wave equations: \n(1) universal patterns in the dynamics of fluxon condensates in the\nsemi-classical limit;\n(2) modulational instability of periodic travelling waves;\n(3) rogue waves on the background of periodic and double-periodic waves. \nMain examples include the sine-Gordon equation\, the nonlinear\nSchroedinger equation\, and the derivative nonlinear Schroedinger\nequation. For the latter equation\, in collaboration with Jinbing Chen\n(South East University\, China) and Jeremy Upsal (University of\nWashington\, USA)\, we adapted the method of nonlinearization of the Lax\nsystem in order to characterize the existence and modulation stability\nof periodic travelling waves. We give precise information on the\nlocation of Lax and stability spectra\, with assistance of numerical\npackage based on the so-called Hill’s method. Particularly interesting\noutcome is the explicit relation between the onset of modulation\ninstability and the existence of a rogue wave (localized solution in\nspace and time) on the background of periodic travelling waves. URL:https://colleges.claremont.edu/ccms/event/applied-math-talk-periodic-travelling-waves-in-nonlinear-wave-equations-modulation-instability-and-rogue-waves-by-dmitry-pelinovsky-mcmaster-university-canada/ LOCATION:Zoom meeting\, United States CATEGORIES:Applied Math Seminar END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210324T161500 DTEND;TZID=America/Los_Angeles:20210324T173000 DTSTAMP:20260415T141019 CREATED:20210204T004055Z LAST-MODIFIED:20210312T000436Z UID:2170-1616602500-1616607000@colleges.claremont.edu SUMMARY:Our muscles aren't one-dimensional fibres (Prof. Nilima Nigam) DESCRIPTION:Title: Our muscles aren’t one-dimensional fibres. \nAbstract: Skeletal muscles possess rather amazing mechanical properties. They possess an intricate structure\, and behave nonlinearly in response to mechanical stresses. In the 1910s\, A.V. Hill observed muscles heat when they contract\, but not when they relax. Based on experiments on frogs he posited a mathematical description of skeletal muscles which approximated muscle as a 1-dimensional nonlinear and massless spring. This has been a remarkably successful model\, and remains in wide use. Recently\, we’ve realized that skeletal muscle is three dimensional\, has mass\, and fairly complicated structure. I’ll present some work on a mathematical model which captures some of this complexity. \nDr. Nilima Nigam is Professor at Simon Fraser University. URL:https://colleges.claremont.edu/ccms/event/nilima-nigam/ LOCATION:Zoom CATEGORIES:Colloquium ORGANIZER;CN="Helen Wong":MAILTO:hwong@cmc.edu END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210329T150000 DTEND;TZID=America/Los_Angeles:20210329T160000 DTSTAMP:20260415T141019 CREATED:20210113T011843Z LAST-MODIFIED:20210325T164523Z UID:2115-1617030000-1617033600@colleges.claremont.edu SUMMARY:Applied math. talk: Hyperbolicity-Preserving Stochastic Galerkin Method for Shallow Water Equations by Dihan Dai\, Department of Mathematics\, University of Utah DESCRIPTION:Abstract: The system of shallow water equations and related models are\nwidely used in oceanography to model hazardous phenomena such as tsunamis\nand storm surges. Unfortunately\, the inherent uncertainties in the system\nwill inevitably damage the credibility of decision-making based on the\ndeterministic model. The stochastic Galerkin (SG) method seeks a solution\nby applying the Galerkin method to the stochastic domain of the equations\nwith uncertainty. However\, the resulting system may fail to preserve the\nhyperbolicity of the original model. In this talk\, we will discuss a\nstrategy to preserve the hyperbolicity of the stochastic systems. We will\nalso discuss a well-balanced hyperbolicity-preserving central-upwind\nscheme for the random shallow water equations and illustrate the\neffectiveness of our schemes on some challenging numerical tests. URL:https://colleges.claremont.edu/ccms/event/applied-math-talk-by-dihan-dai-department-of-mathematics-university-of-utah/ LOCATION:Zoom meeting\, United States CATEGORIES:Applied Math Seminar END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/Los_Angeles:20210331T161500 DTEND;TZID=America/Los_Angeles:20210331T173000 DTSTAMP:20260415T141019 CREATED:20210204T004224Z LAST-MODIFIED:20210312T000546Z UID:2172-1617207300-1617211800@colleges.claremont.edu SUMMARY:An ideal convergence: an example in noncommutative metric geometry (Prof. Konrad Aguilar) DESCRIPTION:Title: An ideal convergence: an example in noncommutative metric geometry \nAbstract: \nThe ability to calculate the distance between sets (rather than just distance between points) has found applications in geometry and group theory as well as various branches of applied mathematics. The Hausdorff distance and the Gromov-Hausdorff distance are standard distances used in these applications. Moreover\, a certain generalization of the Gromov-Hausdorff distance called the quantum Gromov-Hausdorff distance was built by M. A. Rieffel to answer some questions from physics about operator algebras\, which are generalizations of algebras of complex-valued square matrices. In another direction\, J.M.G. Fell introduced a notion of convergence of ideals of a given operator algebra. Can the quantum Gromov-Hausdorff distance also be used to establish convergence of the associated quotient algebras? We discuss this for certain operator algebras called approximately finite-dimensional (AF) C*-algebras\, which can be represented by infinite graphs called Bratteli diagrams where the ideals and quotients are represented by subgraphs. It is the movement of the quotient graphs with respect to the ideal graphs that motivates our question and its answer. The main example we discuss will be given by graph representations of irrational numbers built by their associated continued fractions. (This talk contains joint work with Samantha Brooker\, Frédéric Latrémolière\, and Alejandra López). \nProfessor Konrad Aguilar is Assistant Professor at Pomona College. URL:https://colleges.claremont.edu/ccms/event/konrad-aguilar/ LOCATION:Zoom CATEGORIES:Colloquium ORGANIZER;CN="Helen Wong":MAILTO:hwong@cmc.edu END:VEVENT END:VCALENDAR