BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Department of Mathematics - ECPv4.6.10.1//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:Department of Mathematics
X-ORIGINAL-URL:https://math.sciences.ncsu.edu
X-WR-CALDESC:Events for Department of Mathematics
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180226T110000
DTEND;TZID=America/New_York:20180226T120000
DTSTAMP:20180223T023412
CREATED:20180122T190419Z
LAST-MODIFIED:20180216T151527Z
UID:11434-1519642800-1519646400@math.sciences.ncsu.edu
SUMMARY:Seth Sullivant\, NC State\, Algebraic Statistical Models in Phylogenetics
DESCRIPTION:Phylogenetics is the branch of mathematical biology concerned with constructing evolutionary relationships between collections of species. These lectures will introduce these models\, in particular emphasizing the ways that algebraic statistics can be used to analyze properties of the models. Viewed from the perspective of algebraic statistics\, the corresponding algebraic varieties that arise are often familiar varieties from combinatorial algebraic geometry\, including toric varieties and secant varieties. \n
URL:https://math.sciences.ncsu.edu/event/seth-sullivant-nc-state-algebraic-statistical-models-in-phylogenetics-2018-02-26/
CATEGORIES:Phylogenetics and Evolutionary Biology Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180226T150000
DTEND;TZID=America/New_York:20180226T160000
DTSTAMP:20180223T023412
CREATED:20180216T152105Z
LAST-MODIFIED:20180216T152105Z
UID:11820-1519657200-1519660800@math.sciences.ncsu.edu
SUMMARY:Nathan Reading\, NC State\, To scatter or to cluster?
DESCRIPTION:Scattering diagrams arose in the algebraic-geometric theory of mirror symmetry. Recently\, Gross\, Hacking\, Keel\, and Kontsevich applied scattering diagrams to prove many longstanding conjectures about cluster algebras. Scattering diagrams are certain collections of codimension-1 cones\, each weighted with a formal power series. In this talk\, I will introduce cluster scattering diagrams and their connection to cluster algebras\, focusing on rank-2 (i.e. 2-dimensional) examples. Even 2-dimensional cluster scattering diagrams are not well-understood in general. I will show how the two-dimensional “affine-type” cases can be constructed using cluster algebras and describe a surprising appearance of the Narayana numbers in the two-dimensional affine case. If time allows\, I will discuss a general proof that consistent scattering diagrams cut space into a fan. \n\n
URL:https://math.sciences.ncsu.edu/event/nathan-reading-nc-state-to-scatter-or-to-cluster/
CATEGORIES:Algebra and Combinatorics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180226T153000
DTEND;TZID=America/New_York:20180226T160000
DTSTAMP:20180223T023412
CREATED:20180111T185956Z
LAST-MODIFIED:20180131T214435Z
UID:11310-1519659000-1519660800@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-20-2018-02-28/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180226T160000
DTEND;TZID=America/New_York:20180226T170000
DTSTAMP:20180223T023412
CREATED:20180222T193638Z
LAST-MODIFIED:20180222T193638Z
UID:11856-1519660800-1519664400@math.sciences.ncsu.edu
SUMMARY:John Lowengrub\, University of California\, Irvine\, BioDDFT: A hybrid continuum-discrete mechanical collective cell model
DESCRIPTION:The regulation of cell division\, cell sizes and cell arrangements is central to tissue morphogenesis. To study these processes\, we develop a mechanistic hybrid continuum-discrete mathematical model of cell dynamics that has advantages over previous approaches. This model borrows ideas from statistical physics\, materials science and applied mathematics and follows the framework of dynamic density functional theory. This approach provides a strategy for coarse-graining systems of stochastically interacting particles. By appropriately accounting for cell size and shape variability\, we obtain a system of continuum equations that are able to capture plastic\, viscoelastic and elastic deformations in the clusters while providing single-cell resolution. The discrete component of the model implements cell division and thus influences cell sizes and shapes that couple to the continuum equations. We present efficient numerical methods for solving the coupled systems of equations and validate the model using recent in vitro studies of epithelial cell colonies using Madin-Darby canine kidney cells. In good agreement with the experiments\, we find that mechanical interactions and constraints on the local expansion of cell size cause inhibition of cell motion and reductive cell division. This leads to successively smaller cells and a transition from exponential to quadratic growth of the colony that is associated with the emergence of short-range ordering and a constant-thickness proliferating rim of cells at the cluster edge. We then discuss extensions of the model to account for different cell types\, including stem\, progenitor and terminally differentiated cells\, that are needed to model stratified epithelial tissues. Finally\, we describe how this framework can provide a rational approach for upscaling from the subcell and cell scales to tissue scales to obtain new\, tissue-scale governing equations. \n
URL:https://math.sciences.ncsu.edu/event/john-lowengrub-university-of-california-irvine-bioddft-a-hybrid-continuum-discrete-mechanical-collective-cell-model/
CATEGORIES:Special Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180227T150000
DTEND;TZID=America/New_York:20180227T160000
DTSTAMP:20180223T023412
CREATED:20180216T152301Z
LAST-MODIFIED:20180216T152301Z
UID:11823-1519743600-1519747200@math.sciences.ncsu.edu
SUMMARY:Wilkins Aquino\, Duke University\, A Locally Adapted Reduced Basis Method for Solving Risk-Averse PDE-Constrained Optimization Problems
DESCRIPTION:The numerical solution of large-scale risk-averse PDE-constrained optimization problems requires substantial computational effort due to the discretization in physical and stochastic dimensions. Managing the cost is essential to tackle such problems with high dimensional uncertainties. In this work\, we combine an inexact trust-region (TR) algorithm from with a local\, reduced basis (RB) approximation to efficiently solve risk-averse optimization problems with DE constraints. The main contribution of this work is a numerical framework for systematically constructing surrogate models for the TR subproblem and objective function using local sample-based approximations. Under standard assumptions\, the inexact TR algorithm is guaranteed to converge from any initial guess\, provided that errors in the evaluation of the objective function and its gradient using our RB approach are adequately bounded. In this work\, we provide conditions for which our RB approximations satisfy the necessary bounds and demonstrate the performance of our proposed approach through numerical examples. These examples demonstrate that we can efficiently solve risk-averse PDE-constrained optimization problems with significant computational savings when compared to Monte Carlo. \nCollaborators: Drew Kouri\, Sandia National Laboratories and Zilong Zou\, Duke University \n
URL:https://math.sciences.ncsu.edu/event/wilkins-aquino-duke-university-a-locally-adapted-reduced-basis-method-for-solving-risk-averse-pde-constrained-optimization-problems/
CATEGORIES:Numerical Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180228T104000
DTEND;TZID=America/New_York:20180228T113000
DTSTAMP:20180223T023412
CREATED:20171129T145626Z
LAST-MODIFIED:20180219T192435Z
UID:10957-1519814400-1519817400@math.sciences.ncsu.edu
SUMMARY:Jennifer Hom\, Georgia Tech\, Heegaard Floer and homology cobordism
DESCRIPTION:We study applications of Heegaard Floer homology to homology cobordism. In particular\, to a homology sphere Y\, we associate a module HF_conn(Y)\, called the connected Heegaard Floer homology of Y\, and show that this module is invariant under homology cobordism and isomorphic to a summand of HF_red(Y). The definition of this invariant relies on involutive Heegaard Floer homology. This is joint work with Kristen Hendricks and Tye Lidman. \n
URL:https://math.sciences.ncsu.edu/event/jennifer-hom-georgia-tech/
CATEGORIES:Geometry and Topology Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180228T110000
DTEND;TZID=America/New_York:20180228T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11244-1519815600-1519819200@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-02-28/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180228T130000
DTEND;TZID=America/New_York:20180228T140000
DTSTAMP:20180223T023412
CREATED:20180125T231645Z
LAST-MODIFIED:20180222T194626Z
UID:11468-1519822800-1519826400@math.sciences.ncsu.edu
SUMMARY:Elmas Irmak\, University of Michigan\, Simplicial Maps of Complexes of Curves and Mapping Class Groups of Surfaces
DESCRIPTION:I will talk about recent developments on simplicial maps of complexes of curves on both orientable and nonorientable surfaces. I will also talk about joint work with Prof. Luis Paris. We prove that on a compact\, connected\, nonorientable surface of genus at least 5\, any superinjective simplicial map from the two-sided curve complex to itself is induced by a homeomorphism that is unique up to isotopy. As an application we give the classification of injective homomorphisms from finite index subgroups of the mapping class group to the whole group. \n
URL:https://math.sciences.ncsu.edu/event/elmas-irmark-university-of-michigan-simplicial-maps-of-complexes-of-curves-and-mapping-class-groups-of-surfaces/
CATEGORIES:Geometry and Topology Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180228T150000
DTEND;TZID=America/New_York:20180228T160000
DTSTAMP:20180223T023412
CREATED:20180131T220310Z
LAST-MODIFIED:20180131T220310Z
UID:11502-1519830000-1519833600@math.sciences.ncsu.edu
SUMMARY:Lilian Gladden\, Paris 6\, Equilibria via dynamics involving nonautonomous difference equations with affine weights
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/lilian-gladden-paris-6-equilibria-via-dynamics-involving-nonautonomous-difference-equations-with-affine-weights/
CATEGORIES:Differential Equations/Nonlinear Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180307T110000
DTEND;TZID=America/New_York:20180307T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11245-1520420400-1520424000@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-03-07/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180307T143000
DTEND;TZID=America/New_York:20180307T150000
DTSTAMP:20180223T023412
CREATED:20180111T185956Z
LAST-MODIFIED:20180114T025626Z
UID:11311-1520433000-1520434800@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-20-2018-01-24/2018-03-07/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180313T150000
DTEND;TZID=America/New_York:20180313T160000
DTSTAMP:20180223T023412
CREATED:20171005T142533Z
LAST-MODIFIED:20171103T184711Z
UID:10698-1520953200-1520956800@math.sciences.ncsu.edu
SUMMARY:Gabor Pataki\, UNC-Chapel Hill\, Bad semidefinite programs\, linear algebra\, and short proofs
DESCRIPTION:Semidefinite programs (SDPs) — optimization problems with linear constraints\, linear objective\, and semidefinite matrix variables — are some of the most useful\, versatile\, and pervasive optimization problems to emerge in the last 30 years. They find applications in combinatorial optimization\, machine learning\, and statistics\, to name just a few areas. \nUnfortunately\, SDPs often behave pathologically: the optimal values of the primal and dual problems may differ and may not be attained. Such SDPs are theoretically interesting and numerically often difficult\, or impossible to solve. Yet\, the pathological SDPs in the literature look strikingly similar\, and our recent paper (Pataki: Bad semidefinite programs: they all look the same\, SIAM J. Opt 2017)) explained why: it characterized pathological semidefinite systems by certain {\em excluded matrices}\, which are easy to spot in all published examples. \nHere we give short and elementary proofs of these results using mostly techniques from elementary linear algebra. Our main tool is a standard (canonical) form of semidefinite systems\, from which their pathological behavior is easy to verify. The standard form is constructed in a surprisingly simple manner\, using mostly elementary row operations inherited from Gaussian elimination. \n
URL:https://math.sciences.ncsu.edu/event/gabor-pataki-unc-chapel-hill-bad-semidefinite-programs-linear-algebra-and-short-proofs/
CATEGORIES:Numerical Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180314T110000
DTEND;TZID=America/New_York:20180314T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11246-1521025200-1521028800@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-03-14/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180314T150000
DTEND;TZID=America/New_York:20180314T160000
DTSTAMP:20180223T023412
CREATED:20180107T233158Z
LAST-MODIFIED:20180131T220014Z
UID:11137-1521039600-1521043200@math.sciences.ncsu.edu
SUMMARY:Weiwei Hu\, Oklahoma State University\, An Approximating Control Design for Optimal Mixing by Stokes Flows
DESCRIPTION:We consider an approximating control design for optimal mixing of a non-dissipative scalar eld in unsteady Stokes ows. The objective of our approach is to achieve optimal mixing at a given nal time\, via an active control of the ow velocity through boundary inputs. Due to the zero diusivity of the scalar eld\, establishing the well-posedness of its G^aeaux derivative requires high regularity on velocity eld. This condition results in the need to penalize the time derivative of the boundary control in the cost functional. As a result\, the optimality system becomes difficult to solve. Our current approximating approach will provide a more transparent optimality system\, with the set of admissible controls being L^2 in both time and space. This is achieved by first introducing a small diusivity to the scalar equation and then establishing a rigorous analysis of convergence of the approximating control problem to the original one as the diffusivity approaches to zero. Uniqueness of the optimal solution is obtained for the two dimensional case. \n
URL:https://math.sciences.ncsu.edu/event/weiwei-hu-oklahoma-state-university/
CATEGORIES:Differential Equations/Nonlinear Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180314T160000
DTEND;TZID=America/New_York:20180314T170000
DTSTAMP:20180223T023412
CREATED:20180115T221157Z
LAST-MODIFIED:20180117T170053Z
UID:11342-1521043200-1521046800@math.sciences.ncsu.edu
SUMMARY:Zack Morrow\, NC State\, SIAM Student Chapter Tutorial Series
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/zack-morrow-nc-state-siam-student-chapter-tutorial-series/
CATEGORIES:SIAM Student Chapter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180315T160000
DTEND;TZID=America/New_York:20180315T163000
DTSTAMP:20180223T023412
CREATED:20171002T191700Z
LAST-MODIFIED:20171002T191700Z
UID:10651-1521129600-1521131400@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-14/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180315T163000
DTEND;TZID=America/New_York:20180315T173000
DTSTAMP:20180223T023412
CREATED:20171002T191442Z
LAST-MODIFIED:20171002T191442Z
UID:10649-1521131400-1521135000@math.sciences.ncsu.edu
SUMMARY:Michael Overton\, NYU
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/michael-overton-nyu/
CATEGORIES:Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180316T150000
DTEND;TZID=America/New_York:20180316T160000
DTSTAMP:20180223T023412
CREATED:20180115T223715Z
LAST-MODIFIED:20180115T223715Z
UID:11353-1521212400-1521216000@math.sciences.ncsu.edu
SUMMARY:Patricia Hersh\, T. Khai Nguyen\, NC State
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/patricia-hersh-t-khai-nguyen-nc-state/
CATEGORIES:First Year Research Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180321T110000
DTEND;TZID=America/New_York:20180321T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11247-1521630000-1521633600@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-03-21/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180321T143000
DTEND;TZID=America/New_York:20180321T150000
DTSTAMP:20180223T023412
CREATED:20180111T185956Z
LAST-MODIFIED:20180114T025626Z
UID:11313-1521642600-1521644400@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-20-2018-01-24/2018-03-21/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180321T150000
DTEND;TZID=America/New_York:20180321T160000
DTSTAMP:20180223T023412
CREATED:20180131T220433Z
LAST-MODIFIED:20180131T220433Z
UID:11509-1521644400-1521648000@math.sciences.ncsu.edu
SUMMARY:Constantine Dafermos\, Brown University
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/constantine-dafermos-brown-university/
CATEGORIES:Differential Equations/Nonlinear Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180324T091500
DTEND;TZID=America/New_York:20180324T170000
DTSTAMP:20180223T023412
CREATED:20180205T210635Z
LAST-MODIFIED:20180205T210635Z
UID:11552-1521882900-1521910800@math.sciences.ncsu.edu
SUMMARY:Triangle Lectures in Combinatorics
DESCRIPTION:\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nThe Triangle Lectures in Combinatorics is a series of combinatorial workshops held each semester on a Saturday in the Research Triangle region of North Carolina\, funded by the National Science Foundation. The workshop this spring\, the 15th installment of the Triangle Lectures in Combinatorics (TLC)\, will be hosted by North Carolina State University in Raleigh\, North Carolina on Saturday\, March 24\, 2018. It will include four one hour invited talks as well as coffee breaks and ample time for discussions throughout the day. \n \n\nConference Schedule: \n9:15-10am\, coffee and bagels \n10-11am\, Richard Kenyon (Brown University)\, Harmonic functions and the chromatic polynomial \n11-11:30am\, coffee break \n11:30am-12:30pm\, Karola Meszaros (Cornell University)\, Flow polytopes in combinatorics and algebra \n12:30-2:30pm\, lunch break \n2:30-3:30pm\, Ileana Streinu (Smith College)\, Characterizing 3D rigidity: combinatorial and geometric obstructions \n3:30-4pm\, coffee break \n4-5pm\, Seth Sullivant (North Carolina State University)\, Maximum agreement subtrees \n6pm\, Informal conference dinner (details to be announced later) \n\n\nTo preregister for the meeting: send email to Patricia Hersh\, plhersh@ncsu.edu. This is very helpful to us to have people preregister far in advance as much as possible\, specifically helping us to plan for things such as coffee breaks for the appropriate number of participants. \n\nTo apply for participant travel funding: See the conference web site\, http://www.math.ncsu.edu/TLC/ where there is a link to the application form. The second round of funding awards will be made soon after February 25th. It is also possible some additional applications for funding received somewhat beyond that date could also be funded\, depending upon remaining availability of funds at that point. \n\n \nPractical information: See the conference web site\, http://www.math.ncsu.edu/TLC/ where practical information (hotels\, parking\, campus map\, etc.) may be found\, and where more such information may be posted as the meeting gets closer. \nTalk titles and abstracts:Richard Kenyon (Brown University) \nTitle: Harmonic functions and the chromatic polynomial \nAbstract: The chromatic polynomial X(n) of a graph counts the number of proper colorings with n colors. For each negative integer n we show how to compute |X(n)| as the degree of a certain rational mapping. This mapping arises from the “Dirichlet problem” of finding a harmonic function with fixed boundary values. Our techniques also allows us to equate |X(n)| with a certain set of acyclic orientations of a related graph. This is joint work with Wayne Lam. \nKarola Mészáros (Cornell University) \nTitle: Flow polytopes in combinatorics and algebra \nAbstract: The flow polytope FG(v) is associated to a graph G on the vertex set {1\,…\, n} with edges directed from smaller to larger vertices and a netflow vector v=(v1\,…\, vn) in Zn. The points of FG(v) are nonnegative flows on the edges of G so that flow is conserved at each vertex. Postnikov and Stanley established a remarkable connection of flow polytopes and Kostant partition functions two decades ago\, developed further by Baldoni and Vergne. Since then\, flow polytopes have been discovered in the context of Schubert and Grothendieck polynomials and the space of diagonal harmonics\, among others. This talk will survey a selection of results about the ubiquitous flow polytopes. \nIleana Streinu (Smith College) \nTitle: Characterizing 3D rigidity: combinatorial and geometric obstructions \nAbstract: In spite of many conjectures and approaches spanning the last 30 years\, a combinatorial characterization of 3D rigid graphs (generic bar-and-joint frameworks) remains elusive. I will discuss a few approaches\, all of which fall short of solving the problem due to various combinatorial or geometric obstructions. They include “classical” results (the non-matroidal nature of the underlying “3n-6” sparsity counts and the failure of natural inductive constructions)\, as well as more recent ones: (1) the existence of arbitrarily large nucleation-free graphs (joint work with M. Sitharam and J. Cheng) and (2) a generalization from the finite to the periodic setting\, in which a (rather unusual) definition of genericity has led to a combinatorial characterization via quotient graphs (joint work with C. Borcea). \nSeth Sullivant (North Carolina State University) \nTitle: Maximum agreement subtrees \nAbstract: Probability distributions on the set of trees are fundamental in evolutionary biology\, as models for speciation processes. These probability models for random trees have interesting mathematical features and lead to difficult questions at the boundary of combinatorics and probability. This talk will be concerned with the question of how much two random trees have in common\, where the measure of commonality is the size of the largest agreement subtree. The case of maximum agreement subtrees of pairs of random comb trees is equivalent to studying longest increasing subsequences of random permutations\, and has connections to random matrices. This elementary talk will try to give a sense of what is known (not very much) and what is unknown (lots!) about this problem. \n\n\n\n\n\nWe would appreciate if you could forward this announcement to others you know who may be interested in participating.\n\nWe hope you will be able to attend!\n\nSpring 2018 TLC Organizing committee: Ricky Liu\, chair (NCSU)\, Patricia Hersh (NCSU) and Cynthia Vinzant (NCSU). \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
URL:https://math.sciences.ncsu.edu/event/triangle-lectures-in-combinatorics/
CATEGORIES:Special Events
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180328T110000
DTEND;TZID=America/New_York:20180328T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11248-1522234800-1522238400@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-03-28/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180328T143000
DTEND;TZID=America/New_York:20180328T150000
DTSTAMP:20180223T023412
CREATED:20180111T185956Z
LAST-MODIFIED:20180114T025626Z
UID:11314-1522247400-1522249200@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-20-2018-01-24/2018-03-28/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180328T150000
DTEND;TZID=America/New_York:20180328T160000
DTSTAMP:20180223T023412
CREATED:20180115T221855Z
LAST-MODIFIED:20180115T221855Z
UID:11344-1522249200-1522252800@math.sciences.ncsu.edu
SUMMARY:Shaina Race\, NC State\, SIAM Student Chapter Data Science Lecture Series
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/shaina-race-nc-state-siam-student-chapter-data-science-lecture-series/
CATEGORIES:SIAM Student Chapter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180403T150000
DTEND;TZID=America/New_York:20180403T160000
DTSTAMP:20180223T023412
CREATED:20180131T220627Z
LAST-MODIFIED:20180131T220627Z
UID:11510-1522767600-1522771200@math.sciences.ncsu.edu
SUMMARY:Raymond Yat Tin\, UCLA\, An algorithm for overcoming the curse of dimensionality in Hamilton-Jacobi equations
DESCRIPTION:In this talk we discuss an algorithm to overcome the curse of dimensionality\, in possibly non-convex/time/state-dependent Hamilton-Jacobi partial differential equations. They may arise from optimal control and differential game problems\, and are generally difficult to solve numerically in high dimensions. \nA major contribution of our works is to consider an optimization problem over a single vector of the same dimension as the dimension of the HJ PDE instead. To do so\, we consider the new approach using Hopf-type formulas. The sub-problems are now independent and they can be implemented in an embarrassingly parallel fashion. That is ideal for perfect scaling in parallel computing. \nThe algorithm is proposed to overcome the curse of dimensionality when solving high dimensional HJ PDE. Our method is expected to have application in control theory\, differential game problems\, and elsewhere. This approach can be extended to the computational of a hamilton-Jacobi equation in the Wasserstein space\, and is expected to have applications in mean field control problems\, optimal transport and mean field games. \n
URL:https://math.sciences.ncsu.edu/event/raymond-yat-tin-ucla-an-algorithm-for-overcoming-the-curse-of-dimensionality-in-hamilton-jacobi-equations/
CATEGORIES:Differential Equations/Nonlinear Analysis Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180404T110000
DTEND;TZID=America/New_York:20180404T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11249-1522839600-1522843200@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-04-04/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180404T153000
DTEND;TZID=America/New_York:20180404T160000
DTSTAMP:20180223T023412
CREATED:20171002T192730Z
LAST-MODIFIED:20171002T192730Z
UID:10655-1522855800-1522857600@math.sciences.ncsu.edu
SUMMARY:Tea and Cookies
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/tea-and-cookies-15/
CATEGORIES:Departmental Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180404T160000
DTEND;TZID=America/New_York:20180404T170000
DTSTAMP:20180223T023412
CREATED:20171002T192228Z
LAST-MODIFIED:20171002T192228Z
UID:10653-1522857600-1522861200@math.sciences.ncsu.edu
SUMMARY:Lisa Fauci\, Tulane University
DESCRIPTION:
URL:https://math.sciences.ncsu.edu/event/lisa-fauci-tulane-university/
CATEGORIES:Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20180411T110000
DTEND;TZID=America/New_York:20180411T120000
DTSTAMP:20180223T023412
CREATED:20180110T175323Z
LAST-MODIFIED:20180110T175323Z
UID:11250-1523444400-1523448000@math.sciences.ncsu.edu
SUMMARY:AWM weekly brown bag lunch
DESCRIPTION:The Association for Women in Mathematics (AWM) will be hosting our weekly brown bag lunch. Attendees bring their own lunches\, and have the opportunity to be in a casual discussion environment\, while we provide a tasty treat! AWM is NOT exclusively for women\, and we would like to emphasize that everyone is welcome join us at this weekly event\, including undergraduates\, graduate students\, and faculty members. \n
URL:https://math.sciences.ncsu.edu/event/awm-weekly-brown-bag-lunch-3/2018-04-11/
CATEGORIES:Association for Women in Mathematics
END:VEVENT
END:VCALENDAR