BEGIN:VCALENDAR
PRODID:PRODID:-//math.duke.edu mcal v2.0//EN
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VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260414T191500Z
DTEND:20260414T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13776
SUMMARY:Applied Math And Analysis Seminar : Alexey Cheskidov (Westlake Uni
 versity)
DESCRIPTION:Cancelled\n\n[ https://sites.math.duke.edu/mcal?abstract-13776
  ]
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260415T173000Z
DTEND:20260415T183000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13729
SUMMARY:Algebraic Geometry Seminar : Joaquí­n Moraga (UCLA\, Mathematics)
DESCRIPTION:Cluster type varieties\n\n[ https://sites.math.duke.edu/mcal?a
 bstract-13729 ]\n\nIn this talk\, I will introduce a new class of algebrai
 c varieties that has been of recent interest\; cluster type varieties.\nTh
 ese are compactifications of algebraic tori in such a way that the volume 
 form has no zeros on the compactifications. \nThe second aim of this talk 
 is to show some main properties and characteristics of cluster type variet
 ies. \nFinally\, we will show some new results toward understanding cluste
 r type varieties from the perspective of the complexity and degenerations.
LOCATION:324 Gross Hall
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260415T185000Z
DTEND:20260415T195000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13632
SUMMARY:Number Theory Seminar : Anurag Sahay (Purdue University)
DESCRIPTION:Two variations on the theme of divisor correlations\n\n[ https
 ://sites.math.duke.edu/mcal?abstract-13632 ]\n\nThe correlations between $
 d(n)$ and $d(n+h)$\, where $d(n)$ is the divisor-counting function and $h$
  is a possibly varying non-zero integer are a classical topic in analytic 
 number theory\, going back to Ingham. It is intimately related to the four
 th moment of the Riemann zeta function. After a quick review of the histor
 y of this problem\, we will discuss two recent variants that arose in our 
 work.\n\nIn the first variant\, we will replace the integers with shifted 
 integers $n+\\alpha$\, where $\\alpha$ is an irrational number. This arose
  in work joint with Winston Heap on the fourth moment of the Hurwitz zeta 
 function and has connections to Diophantine approximation.\n\nIn the secon
 d variant\, we will replace the integers with the ring of polynomials over
  a finite field. This was investigated in work joint with Alexandra Florea
 \, Matilde Lalín\, and Amita Malik\, where we extended the range of unifor
 mity in $h$ for which an asymptotic formula is available\, building on ear
 lier work of Conrey--Florea\, Gorodestky\, Woo and Yiasemides. The main ne
 w input here is a Voronoi summation formula for the divisor function\, whi
 ch appears to be novel in this setting.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260416T180000Z
DTEND:20260416T190000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13841
SUMMARY:Special Analysis Seminar : Sam Looi (Caltech)
DESCRIPTION:Global Regularity for a Viscous Dyadic Model of the Navier-Sto
 kes Equations\n\n[ https://sites.math.duke.edu/mcal?abstract-13841 ]\n\nDy
 adic shell models are infinite systems of ODEs that retain the quadratic n
 onlinearity\, energy identity\, and scaling of the 3D incompressible Navie
 r-Stokes equations. Such models can be realized as averaged Navier-Stokes 
 equations at the PDE level\, and some of them blow up in finite time despi
 te satisfying the energy identity\, showing that these structural features
  do not preclude singularity formation. Among dyadic models with these fea
 tures\, the Obukhov model is distinguished by its regulated cascade mechan
 ism: the inviscid version is globally regular. However\, the inviscid proo
 f relies on exact energy conservation\, which viscosity destroys. We prove
  that the viscous Obukhov model is globally regular for all initial data i
 n the critical Sobolev space and above. The proof introduces a critical re
 scaling that shows a viscous activation threshold for each shell\, and est
 ablishes regularity by showing that two competing scales\, viscous damping
  and nonlinear growth\, become incompatible at high frequencies.
LOCATION:324 Gross Hall
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260416T191500Z
DTEND:20260416T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13785
SUMMARY:Probability Seminar : Jeanne Boursier (Columbia University)
DESCRIPTION:Phase transitions for the 2D two-component Coulomb gas\n\n[ ht
 tps://sites.math.duke.edu/mcal?abstract-13785 ]\n\nThe 2D two-component Co
 ulomb gas is a planar system of positive and negative point charges intera
 cting via a logarithmic potential. At a certain temperature\, opposite cha
 rges bind together into dipoles. As the temperature decreases\, the system
  exhibits an infinite sequence of phase transitions driven by the clusteri
 ng of dipoles into multipoles. This sequence accumulates at the ``Berezins
 kii-Kosterlitz-Thouless'' temperature. \n\nI will discuss joint work with 
 Sylvia Serfaty which establishes these transitions rigorously. Our proof d
 evelops a new framework based on adaptive cluster expansions and electrost
 atic estimates.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260417T160000Z
DTEND:20260417T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13845
SUMMARY:Topology And Hydrodynamics Seminar : Naji Sarsam (Duke University\
 , Mathematics)
DESCRIPTION:TBA\n\n[ https://sites.math.duke.edu/mcal?abstract-13845 ]
LOCATION:Gross 359
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260417T160000Z
DTEND:20260417T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13766
SUMMARY:Mathematical Biology Seminar : Linh Do (Duke University\, Biostati
 stics and Bioinformatics)
DESCRIPTION:From Equations to Infection: Mechanistic Bayesian Models for V
 iral Dynamics and Correlates of Protection\n\n[ https://sites.math.duke.ed
 u/mcal?abstract-13766 ]\n\nUnderstanding why some exposed individuals beco
 me detectably infected while others remain protected is a central problem 
 in infectious disease biology. In this talk\, we present a mechanistic Bay
 esian framework that combines within-host viral dynamical systems with lat
 ent-state statistical inference to study infection establishment and clear
 ance. The approach integrates an eclipse-phase ODE model for viral kinetic
 s with a Bayesian mixture formulation\, allowing infection status to be tr
 eated as a hidden dynamical state rather than relying solely on nominal PC
 R positivity.\n\nA central challenge is that longitudinal viral load traje
 ctories are often sparse\, censored\, and only partially observed\, making
  direct subject-level ODE fitting practically non-identifiable. To address
  this\, we use Approximate Bayesian Computation (ABC) to infer posterior u
 ncertainty over kinetic parameters for well-resolved subjects and then con
 struct a posterior bank of plausible trajectory shapes. This bank is subse
 quently used to stabilize inference for subjects with few observations by 
 borrowing uncertainty at the trajectory level.\n\nCoupled with expectation
 -maximization\, this framework yields subject-specific probabilities of pr
 oductive infection while accounting for sparse sampling and heterogeneous 
 trajectory shapes. We show how this approach produces biologically interpr
 etable thresholds of immune protection\, including PD50 estimates for muco
 sal and serum biomarkers\, and reveals cases in which nominal PCR positivi
 ty is mechanistically inconsistent with productive infection.\n\nMore broa
 dly\, this work illustrates how mathematical modeling can bridge noisy lon
 gitudinal data and biological mechanisms to generate interpretable insight
 s into correlates of protection\, viral clearance\, and vaccine-mediated i
 mmunity.
LOCATION:Zoom
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260420T191500Z
DTEND:20260420T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13673
SUMMARY:Geometry/topology Seminar : William Minicozzi (MIT)
DESCRIPTION:TBA\n\n[ https://sites.math.duke.edu/mcal?abstract-13673 ]\n\n
 TBA
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260421T191500Z
DTEND:20260421T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13723
SUMMARY:Applied Math And Analysis Seminar : Thomas Anderson (Rice Universi
 ty)
DESCRIPTION:Integral equation methods for inhomogeneous problems: discreti
 zations and solvers\n\n[ https://sites.math.duke.edu/mcal?abstract-13723 ]
 \n\nMethods based on Green's functions have long been a workhorse for homo
 geneous boundary value problems\, as they lead to integral equations posed
  on the boundary of a region of interest\, with additional special advanta
 ges accruing for exterior problems. Persistent challenges include the need
  to evaluate singular integrals with kernels that decay slowly and require
  special care for efficient computations of long-range interactions. But e
 ven more fundamentally\, the methods have not seen success for inhomogeneo
 us problems for which methods typically involve one or several volume inte
 gral operators (VIOs). We will discuss a class of numerical methods for VI
 Os that rely on analytic regularization: they use Green's identities to re
 gularize the singular kernels in the volume integrals and lead to high-ord
 er accuracy even with the use of standard\, singularity-oblivious triangle
 /tetrahedral quadratures. A complete error analysis\, over 2D and 3D meshe
 s possibly containing curved elements\, for several key VIOs of progressiv
 ely increasing singularity strength that arise in applications will be dis
 cussed. Numerical examples will be presented in the context of (1) IMEX ti
 me-stepping methods for nonlinear PDEs and (2) variable-coefficient scatte
 ring problems arising in inhomogeneous media. For the latter\, a key chall
 enge involves the incorporation of efficient volume preconditioners into i
 terative solvers\, while retaining high-order accuracy in the presence of 
 material discontinuities.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260422T160000Z
DTEND:20260422T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13639
SUMMARY:Colloquium Seminar : Thomas Hou (California Institute of Technolog
 y)
DESCRIPTION:Computer-Assisted Proofs of 3D Euler Singularity and Nonunique
 ness of Leray–Hopf Solutions for the Unforced 3D Navier–Stokes Equations\n
 \n[ https://sites.math.duke.edu/mcal?abstract-13639 ]\n\nWhether the 3D in
 compressible Euler equations can develop a finite-time singularity from sm
 ooth initial data remains one of the central open problems in nonlinear PD
 Es. In this talk\, I will present recent joint work with Dr. Jiajie Chen\,
  in which we rigorously prove finite-time blowup for the 2D Boussinesq equ
 ations and the 3D axisymmetric Euler equations with smooth initial data an
 d smooth boundary. Our approach uses a dynamically rescaled formulation th
 at reduces singularity formation to the long-time stability of an approxim
 ate self-similar blowup profile. A key difficulty is proving the linear st
 ability of a numerically constructed profile. To address this\, we decompo
 se the solution operator into a leading-order part\, which admits sharp st
 ability estimates\, and a finite-rank perturbation\, which is controlled b
 y a computer-assisted proof. I will also discuss recent joint work with Yi
 xuan Wang and Changhe Yang on nonuniqueness of Leray–Hopf solutions to the
  unforced 3D incompressible Navier–Stokes equations. In this setting\, the
  viscous term introduces several new ingredients but also greatly simplifi
 es the analysis: standard $H^1$ estimates suffice\, without the singular w
 eights needed in the inviscid case. A central step is to establish the exi
 stence of a self-similar Leray–Hopf solution and then prove the existence 
 of a second solution by analyzing the stability of the linearized operator
  around this profile and showing that it admits an unstable mode. These re
 sults highlight the fruitful interplay among analysis\, computation\, and 
 rigorous validation in nonlinear PDEs.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260422T185000Z
DTEND:20260422T195000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13721
SUMMARY:Number Theory Seminar : Sug Woo SHIN (UC Berkele)
DESCRIPTION:Vanishing of cohomology for locally symmetric spaces \n\n[ htt
 ps://sites.math.duke.edu/mcal?abstract-13721 ]\n\nWe have multiple approac
 hes to vanishing theorems for the cohomology of Shimura varieties\, via ei
 ther algebraic geometry or automorphic forms. Such theorems have been of i
 nterest with either complex or torsion coefficients. Recently\, results ha
 ve been obtained under various genericity hypotheses by Boyer\, Caraiani-S
 cholze\, Daniels-van Hoften-Kim-Zhang\, Koshikawa\, Hamann-Lee\, Yang-Zhu\
 , and others. I will discuss some conjectures formulated with Koshikawa to
  understand the non-generic case. The more general case of locally symmetr
 ic spaces may also be discussed.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260423T160000Z
DTEND:20260423T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13818
SUMMARY:Frontiers In Mathematics Seminar : Candace Bethea (Brown Universit
 y\, Mathematics)
DESCRIPTION:Symmetry in Enumerative Geometry\n\n[ https://sites.math.duke.
 edu/mcal?abstract-13818 ]\n\nClassical enumerative geometry studies proble
 ms of counting geometric objects satisfying specific conditions. Such coun
 ts are typically expressed as integers\, and can often be obtained using t
 opological invariants like the Euler number. In recent years\, a number of
  refinements of enumerative invariants have emerged\, producing new counts
  and revealing additional structure in classical counts.\n\n\nIn this lect
 ure\, I will describe an approach to understanding symmetries in enumerati
 ve geometry when a finite group acts on the set of solutions to an enumera
 tive problem. This naturally leads to a theory of equivariantly enriched e
 numerative geometry. I will present several examples of equivariant enumer
 ative results\, including a count of rational cubic curves and bitangents 
 to symmetric quartic curves\, joint with a number of authors including K. 
 Wickelgren\, T. Brazelton\, and C. Ravi.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260424T160000Z
DTEND:20260424T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13705
SUMMARY:Mathematical Biology Seminar : Miranda Holmes-Cerfon (University o
 f British Columbia\, Mathematics)
DESCRIPTION:TBA\n\n[ https://sites.math.duke.edu/mcal?abstract-13705 ]\n\n
 TBA
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260424T173000Z
DTEND:20260424T183000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13820
SUMMARY:Frontiers In Mathematics Seminar : Candace Bethea (Brown Universit
 y)
DESCRIPTION:Constructing Equivariant Enumerative Invariants\n\n[ https://s
 ites.math.duke.edu/mcal?abstract-13820 ]\n\nIn the second lecture\, I will
  discuss the homotopy-theoretic techniques underlying the construction of 
 these invariants. Specifically\, I will introduce the Euler number in (der
 ived) equivariant motivic homotopy theory\, joint with C. Ravi\, which is 
 an algebro-geometric analogue of the topological equivariant Euler numbers
  of T. Brazelton and Bethea—Wickelgren. This construction leads to refined
  counts valued in the representation ring of a finite group. I will end by
  sketching how these constructions are used to produce equivariant enumera
 tive results like those discussed in the first lecture.
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260427T191500Z
DTEND:20260427T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13741
SUMMARY:Geometry/topology Seminar : Ruobing Zhang (University of Californi
 a\, San Diego)
DESCRIPTION:TBA\n\n[ https://sites.math.duke.edu/mcal?abstract-13741 ]\n\n
 TBA
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260429T173000Z
DTEND:20260429T183000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13744
SUMMARY:Algebraic Geometry Seminar : Laure Flapan (Michigan State Universi
 ty)
DESCRIPTION:TBD\n\n[ https://sites.math.duke.edu/mcal?abstract-13744 ]\n\n
 TBD
LOCATION:Gross 324
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260429T185000Z
DTEND:20260429T195000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13746
SUMMARY:Number Theory Seminar : Ashay Burungale (University of Texas at Au
 stin)
DESCRIPTION:TBA\n\n[ https://sites.math.duke.edu/mcal?abstract-13746 ]\n\n
 TBA
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260916T160000Z
DTEND:20260916T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13809
SUMMARY:Gergen Lectures Seminar : Karen Smith (University of Michigan)
DESCRIPTION:Gergen Lecture I\n\n[ https://sites.math.duke.edu/mcal?abstrac
 t-13809 ]
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260916T191500Z
DTEND:20260916T201500Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13812
SUMMARY:Gergen Lectures Seminar : Karen Smith (University of Michigan)
DESCRIPTION:Gergen Lecture II\n\n[ https://sites.math.duke.edu/mcal?abstra
 ct-13812 ]\n\nTBD
LOCATION:Room TBD
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260917T160000Z
DTEND:20260917T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13811
SUMMARY:Gergen Lectures Seminar : Karen Smith (University of Michigan)
DESCRIPTION:Gergen Lecture III\n\n[ https://sites.math.duke.edu/mcal?abstr
 act-13811 ]
LOCATION:Room TBD
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260918T160000Z
DTEND:20260918T170000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13810
SUMMARY:Gergen Lectures Seminar : Karen Smith (University of Michigan)
DESCRIPTION:Gergen Lecture IV\n\n[ https://sites.math.duke.edu/mcal?abstra
 ct-13810 ]
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20260414T235414Z
DTSTART:20260923T173000Z
DTEND:20260923T183000Z
ORGANIZER;CN=Duke Mathematics:
UID:duke_math_mcal_13690
SUMMARY:Number Theory Seminar : Ellen Eischen
DESCRIPTION:Number Theory Seminar\n\n[ https://sites.math.duke.edu/mcal?ab
 stract-13690 ]
LOCATION:Physics 119
CLASS:DEFAULT
TRANSP:TRANSPARENT
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR