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PRODID:-//Mathematics Department//NONSGML mathical.php//EN
X-WR-CALNAME:Mathematics Department
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c16c1@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240123T103000
DTEND;TZID=America/New_York:20240123T113000
CATEGORIES:Combinatorics Seminar
SUMMARY:Rebecca Whitman: A Hereditary Generalization of
Nordhaus-Gaddum Graphs
DESCRIPTION:Nordhaus and Gaddum proved in 1956 that the sum of the
chromatic number Chi of a graph G and its complement is at most |G|
+ 1. The Nordhaus-Gaddum graphs are the class of graphs satisfying
this inequality with equality\, and are well-understood. In this
talk we consider a hereditary generalization: graphs G for which all
induced subgraphs H of G have that the sum of the chromatic numbers
of H and its complement is at least |H|. We characterize the
forbidden induced subgraphs of this class and find its intersection
with a number of common classes\, including line graphs. We also
discuss Chi-boundedness and algorithmic optimization results.
LOCATION:Zoom
URL:https://math.dartmouth.edu/~comb/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c172b@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240125T132000
DTEND;TZID=America/New_York:20240125T142000
CATEGORIES:Functional Analysis Seminar
SUMMARY:Mohammad Javad Latifi: An elementary prelude to quantum
fields\, I
DESCRIPTION:In my two talks on quantum field theory\, I aim to
explore the mathematical aspects of the theory while keeping it
relatable for physicists.\nDuring the first talk\, I'll discuss the
Lagrangian formulation of Euclidean field theories. We'll also dive
into Feynman diagrams\, exploring their importance from a
probabilistic standpoint. At times\, we'll consider the idea that
quantum field theory might have been discovered through a
mathematical lens (much like calculus) with potential applications
beyond the realm of physics. In my second talk\, I plan to visit
measure theory in infinite dimensions and review rigorous
constructions of quantum field theories.
LOCATION:307 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c177c@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240130T140000
DTEND;TZID=America/New_York:20240130T150000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Mario Bencomo: Topics in Differential Equations\, Inverse
Problems\, and Optimal Control
DESCRIPTION:This talk covers a body of research under the category
of optimization problems with differential equations as
constraints\, a unifying framework for some inverse and optimal
control problems. The talk will focus on challenges associated with
discretizing and estimating seismic sources as multipoles and
discrete adjoint computations for relaxation Runge-Kutta methods.
Accurate representation and estimation of seismic sources is crucial
to the accuracy of imaging algorithms in exploration seismology. In
order to account for source anisotropy\, we model seismic sources of
point-support as multipoles\, i.e.\, a finite series of derivatives
of the spatial delta function. We present a method for discretizing
multipole sources in a finite difference setting. The multipole
source inverse problem results in a highly ill-conditioned linear
least squares problem which presents a challenge for iterative
solvers such as conjugate gradient (CG). We propose a preconditioner
consisting of time differo-integral operators based on analytical
solutions to the wave equation to accelerate CG iterations.
Relaxation Runge-Kutta (RRK) methods reproduce a fully discrete
conservation of entropy for entropy stable semi-discretizations of
nonlinear conservation laws. In this talk\, we derive the discrete
adjoint of RRK schemes\, which are applicable to
discretize-then-optimize approaches for optimal control problems.
Numerical experiments demonstrate the importance of appropriately
treating the relaxation parameter when computing the discrete
adjoint.
LOCATION:Zoom
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c17d6@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240201T142500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Santiago Arango-Piñeros: Counting points on $x^2+y^2 = z^4$
and cyclic 5-isogenies of elliptic curves over $\\mathbb{Q}$
DESCRIPTION:We study the asymptotic order of growth of the number of
minimal integral solutions to the generalized Fermat equation
$x^2+y^2 = z^4$ and relate it to the asymptotic count of cyclic
$5$-isogenies of elliptic curves over $\\mathbb{Q}$\, with bounded
naive height. This is forthcoming work in collaboration with Changho
Han\, Oana Padurariu\, and Sun Woo Park.
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1823@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240206T103000
DTEND;TZID=America/New_York:20240206T113000
CATEGORIES:Combinatorics Seminar
SUMMARY:Combinatorics Seminar
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~comb/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1869@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240206T143000
DTEND;TZID=America/New_York:20240206T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Jeremy Manning : How do our thoughts take shape?
DESCRIPTION:How our brains support our ongoing conscious thoughts\,
and how (and what) we remember are some of the greatest mysteries of
our species. My lab is pushing our understanding of these questions
using computational models and neuroimaging. In my talk\, I'll focus
on our work using natural language processing models to characterize
the content of people's experiences\, memories\, knowledge\,
behaviors\, and interactions.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c18b4@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240206T150000
DTEND;TZID=America/New_York:20240206T160000
CATEGORIES:Logic Seminar
SUMMARY:Justin Miller: The Computability of Chip-Firing on Graphs\,
Part 3
LOCATION:Kemeny 201
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c18fa@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240208T100000
CATEGORIES:Topology Seminar
SUMMARY:Oleg Lazarev: Weinstein domains: a symplectic geometer's
handlebodies
DESCRIPTION:Weinstein domains are symplectic analogs of smooth
handlebodies and come equipped with decompositions with elementary
symplectic pieces. As a result\, they are easy to construct\, have
computable invariants\, and include classical examples like
cotangent bundles. After giving some background\, I will survey
several questions (and recent answers) about Weinstein domains\,
many of which are motivated by analogous questions in smooth
topology and have categorical interpretations. For example\, the
minimal number of Weinstein handles in a Weinstein domain is related
to the Grothendieck group of its Fukaya category while the minimal
number of "elementary" Weinstein sectors needed to cover a Weinstein
domain is related to the Rouquier dimension of its Fukaya category\;
in the case of the cotangent bundle of M\, this Rouquier dimension
is bounded by the LS-category of M.
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~topology
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1949@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240208T132000
DTEND;TZID=America/New_York:20240208T142000
CATEGORIES:Geometry Seminar
SUMMARY:Tamara Kucherenko: Realization of Anosov Diffeomorphisms on
the Torus
DESCRIPTION:We consider area preserving Anosov maps on the
two-dimensional torus within a fixed homotopy class. We show that
the set of pressure functions for Anosov diffeomorphisms with
respect to the geometric potential is equal to the set of pressure
functions for the linear Anosov automorphism with respect to
H\\"{o}lder potentials. We use this result to provide a negative
answer to the $C^{1+\\alpha}$ version of the question posted in the
paper by A. Erchenko: ``if two homotopic smooth area preserving
Anosov difeomorphisms have identical pressure functions for their
geometric potentials\, must they be $C^\\infty$ conjugate?" (This is
based on joint work with Anthony Quas.)
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~gts/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c199d@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240208T151500
CATEGORIES:Math Colloquium
SUMMARY:Sarah Mason: The quest for quasisymmetric Macdonald
polynomials
DESCRIPTION:Macdonald polynomials are a two-parameter generalization
of symmetric functions with connections to representation theory\,
geometry\, and combinatorics. A recent breakthrough by Corteel\,
Mandelshtam\, and Williams connecting Macdonald polynomials to the
asymmetric simple exclusion process (ASEP) has paved the way for new
developments in the theory of Macdonald polynomials. In this talk\,
we build on these connections to introduce a quasisymmetric
refinement of Macdonald polynomials as well as several new and more
compact combinatorial formulas for Macdonald polynomials. This is
joint work with Corteel\, Haglund\, Mandelshtam\, and Williams.
LOCATION:Carpenter 13
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c19ea@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240213T103000
DTEND;TZID=America/New_York:20240213T113000
CATEGORIES:Combinatorics Seminar
SUMMARY:Kyle Celano: Chromatic Symmetric Functions and RSK for
3-free Posets
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~comb/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1a30@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240213T142500
DTEND;TZID=America/New_York:20240213T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Aaron Landesman: The distribution of Selmer groups and ranks
of abelian varieties in quadratic twist families over function
fields
DESCRIPTION:The minimalist conjecture predicts that\, in quadratic
twist families of abelian varieties\, half have rank $0$ and half
have rank $1$. This fits into the larger picture of the
Bhargava-Kane-Lenstra-Poonen-Rains heuristics\, which predict the
distribution of Selmer groups of these abelian varieties. In joint
work with Jordan Ellenberg\, we prove a version of these heuristics:
over function fields over the finite field $\\mathbb{F}_q$\, we show
that the above heuristics are correct to within an error term in
$q$\, which goes to $0$ as $q$ grows. The main inputs are a new
homological stability theorem in topology for a generalized version
of Hurwitz spaces and an expression of average sizes of Selmer
groups in terms of the number of rational points on these Hurwitz
spaces over finite fields.
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1a7f@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240213T143000
DTEND;TZID=America/New_York:20240213T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Maryclare Griffin: Testing and estimation for
sparsity-inducing power penalties
DESCRIPTION:Many penalized maximum likelihood estimators correspond
to posterior mode estimators under specific prior distributions.
Appropriateness of a particular class of penalty functions can
therefore be interpreted as the appropriateness of a prior for the
parameters. For example\, the appropriateness of a lasso penalty for
regression coefficients depends on the extent to which the empirical
distribution of the regression coefficients resembles a Laplace
distribution. We give a testing procedure of whether or not a
Laplace prior is appropriate and accordingly\, whether or not using
a lasso penalized estimate is appropriate. Via simulations\, we show
that this testing procedure achieves the desired level and has
enough power to detect violations of the Laplace assumption when the
numbers of observations and unknown regression coefficients are
large. We then introduce an adaptive procedure that chooses a more
appropriate prior and corresponding penalty from the class of
exponential power priors when the null hypothesis is rejected. We
show that this can improve estimation of the regression coefficients
both when they are drawn from an exponential power distribution and
when they are drawn from a spike-and-slab distribution. Last\, this
motivates an improved pathwise coordinate descent method for
estimating regression coefficients assuming an exponential power
prior\, which corresponds to a power penalty. We introduce and
demonstrate the utility of the corresponding new pathwise coordinate
descent method.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1ae0@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240215T100000
CATEGORIES:Topology Seminar
SUMMARY:Andrew Hanlon : Resolutions from symplectic topology
DESCRIPTION:Algebraic objects are often studied by building every
element from a generating set and examining how these generators
interact. We will see how such "resolutions" of objects can be
understood geometrically in certain Fukaya categories and their
relation to classical geometric constructions building a shape out
of simpler pieces. Moreover\, these geometric resolutions can be
applied to obtain new algebraic results and insight via mirror
symmetry. This talk is based on joint work with Hicks and Lazarev.\n
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1b2d@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240215T132000
DTEND;TZID=America/New_York:20240215T142000
CATEGORIES:Functional Analysis Seminar
SUMMARY:Mohammad Latifi-Jebelli: An elementary prelude to quantum
fields\, II
DESCRIPTION: In my two talks on quantum field theory\, I aim to
explore the mathematical aspects of the theory while keeping it
relatable for physicists. During the first talk\, I'll discuss the
Lagrangian formulation of Euclidean field theories. We'll also dive
into Feynman diagrams\, exploring their importance from a
probabilistic standpoint. At times\, we'll consider the idea that
quantum field theory might have been discovered through a
mathematical lens (much like calculus) with potential applications
beyond the realm of physics. In my second talk\, I plan to visit
measure theory in infinite dimensions and review rigorous
constructions of quantum field theories.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1b79@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240220T103000
DTEND;TZID=America/New_York:20240220T113000
CATEGORIES:Combinatorics Seminar
SUMMARY:Gabe Udell: Interpolating between classic and bumpless pipe
dreams
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~comb/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1bc0@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240220T142500
DTEND;TZID=America/New_York:20240220T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Valia Gazaki: Hyperelliptic Curves mapping to Abelian
Surfaces and Applications to Beilinson's Conjecture for zero-cycles
DESCRIPTION:The Chow group of zero-cycles is a generalization to
higher dimensions of the Picard group of a smooth projective curve.
When $X$ is a curve over an algebraically closed field $k$ its
Picard group can be fully understood by the Abel-Jacobi map\, which
gives an isomorphism between the degree zero elements of the Picard
group and the $k$-points of the Jacobian variety of $X$. In higher
dimensions however the situation is much more chaotic\, as the
Abel-Jacobi map in general has a kernel\, which over large fields
like $\\mathbb{C}$ can be enormous. On the other extreme\, a famous
conjecture of Beilinson predicts that if $X$ is a smooth projective
variety over $\\overline{\\mathbb{Q}}$\, then this kernel is zero.
For a variety $X$ with positive geometric genus this conjecture is
very hard to establish. In fact\, there are hardly any examples in
the literature. In this talk I will discuss joint work with Jonathan
Love where we make substantial progress on this conjecture for an
abelian surface $A$. First\, we will describe a very large
collection of relations in the kernel arising from hyperelliptic
curves mapping to $A$. Second\, we will show that at least in the
special case when $A$ is isogenous to a product of two elliptic
curves\, such hyperelliptic curves are plentiful. Namely\, we will
describe a construction that produces for infinitely many values of
$g\\geq 2$ countably many hyperelliptic curves of genus $g$ mapping
birationally into A.
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1c17@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240220T143000
DTEND;TZID=America/New_York:20240220T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Casey Dowdle: Quantum Computing and the Battle for Quantum
Advantage
DESCRIPTION:Quantum computing has gained attention lately for
several reasons\, including academic\, national security\, and
economic interests. Quantum advantage was first claimed in 2019 by
Google in their random circuit sampling experiment. Since then there
have been many other claims of quantum computers performing
calculations faster than classical computers. However\, every claim
so far has been disproven through methods such as spoofing and
tensor network simulation. In this talk I will give a brief overview
of quantum theory\, quantum computing\, and the on-going controversy
over quantum advantage.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1c63@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240220T150000
CATEGORIES:Logic Seminar
SUMMARY:Justin Miller: Effective Dimension Part 1: Gales
LOCATION:Kemeny 201
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1ca9@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240221T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Christopher Jones: Optimizing data assimilation for the
underlying numerical solver with motivation from next generation sea
ice models
DESCRIPTION:Data assimilation (DA) is a process by which information
from the computational solution of a physical model and from
observational data are combined to give a more accurate
characterization of the physical situation under study. DA schemes
are traditionally model-agnostic\, but sophisticated numerical
solvers offer an opportunity for the improvement of DA schemes
through designing them to work in concert with the solver. The
motivation comes from novel models of Arctic sea ice that are based
on numerical solvers aimed at capturing such physical features as
fractures and leads. These include the use of adaptive meshes and
discontinuous Galerkin methods.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1cf5@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240222T100000
CATEGORIES:Topology Seminar
SUMMARY:Ina Petkova: Spectral GRID invariants and Lagrangian
cobordisms
DESCRIPTION:Knot Floer homology is a powerful invariant of knots and
links\, developed by Ozsvath and Szabo in the early 2000s. Among
other properties\, it detects the genus\, detects fiberedness\, and
gives a lower bound to the 4-ball genus. The original definition
involves counting homomorphic curves in a high-dimensional
manifold\, and as a result the invariant can be hard to compute. In
2007\, Manolecu\, Ozsvath\, and Sarkar came up with a purely
combinatorial description of knot Floer homology for knots in the
3-sphere\, called grid homology. Soon after\, Ozsvath\, Szabo\, and
Thurston defined invariants of Legendrian knots using grid homology.
We show that the filtered version of these GRID invariants\, and
consequently their associated invariants in a certain spectral
sequence for grid homology\, obstruct decomposable Lagrangian
cobordisms in the symplectization of the standard contact
structure\, strengthening a result of Baldwin\, Lidman\, and Wong.
This is joint work with Jubeir\, Schwartz\, Winkeler\, and Wong.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1d46@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240222T132000
DTEND;TZID=America/New_York:20240222T142000
CATEGORIES:Geometry Seminar
SUMMARY:Ben Call: Mixing Properties of Equilibrium States for
Systems Beyond Negative Curvature
DESCRIPTION:I will first introduce some known results about
equilibrium states for the geodesic flow in negative curvature. I
will then discuss some tools and techniques that can be used to show
similar results in settings beyond negative curvature\, including
rank one nonpositively curved manifolds and translation surfaces.
Then\, time permitting\, I will discuss upcoming work showing the
Bernoulli property for a class of equilibrium states\, which shows
that they are "the most random" they can be in a qualitative
sense. This is joint work with Dave Constantine\, Alena Erchenko\,
Noelle Sawyer\, and Grace Work.
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~gts/#Feb22
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1d93@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240222T151500
CATEGORIES:Math Colloquium
SUMMARY:Christopher Jones: Rate-Induced Tipping and its Relevance in
a Changing Climate
DESCRIPTION:Tipping in a physical system due to the rate of change
of a driving force is a topic that has been analyzed from a
mathematical perspective over the past decade. We now have a much
better understanding of how it occurs and under what circumstances.
Tipping is usually associated with the possibility\, and fear\, of
abrupt shifts in a physical system\, and many examples occur in the
climate: Greenland ice sheet loss\, break-off of Antarctic
ice-sheets\, boreal forest dieback\, permafrost loss etc. These
tipping scenarios are mostly viewed in terms of bifurcation-based
tipping\, but it may be that rate-induced tipping is the most
relevant for exactly the reason that parameters effecting these
shifts are changing more rapidly than the ability of the system to
adjust. These rate-induced shifts may also be abrupt\, but the
driver is quite different. I will discuss the dynamical systems
behind rate-induced tipping\, open questions\, applications to
climate related systems and interesting new directions in which
noise and rate change are working together.
LOCATION:Carpenter 13
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1de3@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240227T103000
DTEND;TZID=America/New_York:20240227T113000
CATEGORIES:Combinatorics Seminar
SUMMARY:Nadia Lafrenière: Rowmotion on interval-closed sets
DESCRIPTION:Interval-closed sets of a poset are a natural superset
of order ideals.\nRowmotion is an operation on various combinatorial
structures\, including\norder ideals of posets. We initiated the
study of interval-closed sets\nof finite posets from enumerative and
dynamical perspectives. In\nparticular\, we used the generalized
toggle group to define rowmotion on\ninterval-closed sets as a
product of these toggles. Our main theorem is\nan intricate global
characterization of rowmotion on interval-closed\nsets\, which we
show is equivalent to the toggling definition.\nWe also studied
specific posets\; we enumerated interval-closed sets of\nordinal
sums of antichains and completely described their rowmotion\norbits.
We studied interval-closed sets of product of chains
posets\,\nproving further results about enumeration\, while leaving
open some\nimportant questions. This is joint work with Jennifer
Elder\, Erin\nMcNicholas\, Jessica Striker and Amanda Welch.
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~comb/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1e34@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240227T142500
DTEND;TZID=America/New_York:20240227T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Steve Fan (virtual talk): Counting shifted-prime divisors
DESCRIPTION:A shifted prime is a number of the form $p-1$\, where
$p$ is prime. For every positive integer $n$\, let $\\omega^*(n)$
denote the number of positive divisors of $n$ that are shifted
primes. First studied by Prachar in an influential paper from 70
years ago\, the function $\\omega^*$ shares some interesting
features with the divisor function $\\tau$ and the prime-divisor
function $\\omega$\, but its distribution still remains a mystery.
The study of this function was recently picked up by Murty and Murty
who proved lower and upper bounds for the second moment of
$\\omega^*$\, and shortly after their work\, Ding obtained a
refinement of their lower bound and suggested a possible asymptotic
formula. In this talk\, we continue this trend of study by
investigating the higher moments of $\\omega^*$ and other related
problems. This is joint work with Carl Pomerance.
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1e83@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240227T143000
DTEND;TZID=America/New_York:20240227T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Alex McAvoy: Evaluating mutation-selection dynamics in
structured populations
DESCRIPTION:Evolutionary processes in structured populations are
often studied under the assumption that traits/behaviors/types
spread from vertex to vertex faithfully\, with no mutation of types
as they propagate. While some systems do have zero or small mutation
rates\, these models are limited in their expressiveness due to
their inability to capture organisms with more frequent mutations.
Such systems could be genetic in nature (e.g.\, viruses) or cultural
(e.g.\, mutation as exploration of nearby behaviors). In this talk\,
I will describe a modeling approach that appeared around 15 years
ago and describe recent work with a colleague that allows one to
evaluate this class of models on heterogeneous networks. If time
permits\, I will briefly discuss some limitations of this model as
well as plans for future work to make it more realistic.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1ed0@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240229T100000
CATEGORIES:Topology Seminar
SUMMARY:Mike Miller Eismeier: Instantons\, indefinite 4-manifolds\,
and Dehn surgery
DESCRIPTION:In joint work with Ali Daemi\, we investigate an
invariant q_3(Y) in Z associated to a homology 3-sphere\, and a
mod-2 instanton homology analogue of the d-invariant in Heegaard
Floer theory. Whereas the d-invariant is nondecreasing under
negative-definite cobordisms\, q_3 satisfies an inequality valid for
all cobordisms W: Y -> Y' with H_1(W\; Z) free of 2-torsion\, even
indefinite ones: we have\n-b^+(W)
LOCATION:Kemeny 307
URL:https://math.dartmouth.edu/~topology
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1f1f@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240229T132000
DTEND;TZID=America/New_York:20240229T142000
CATEGORIES:Geometry Seminar
SUMMARY:Ian Adelstein: Geometric Manifold Learning
DESCRIPTION:With the advent of high dimensional high throughput data
in many fields including biomedicine\, social science\, physics\,
finance\, etc\, there is an increasing need to understand the
topology (shape\, structure) and geometry (intrinsic distance\,
curvature) of the data. This process starts with the manifold
hypothesis: that high dimensional data actually live on or near a
much lower dimensional manifold. One can then study the geometric
and topological properties of this manifold to reveal important
features of the data. The primary goal of this talk will be to
introduce the main bridge between the data manifold and its
geometry: the spectral theory for the graph Laplacian. I will also
discuss some recent projects that explore the geometry of the data
manifold.
LOCATION:307 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1f6c@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240305T142500
DTEND;TZID=America/New_York:20240305T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Sachi Hashimoto: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c1fb2@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240305T143000
DTEND;TZID=America/New_York:20240305T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Chris Vales: Energy conservative quadrature based
hyperreduction of Lagrangian hydrodynamics problems
DESCRIPTION:Dimension reduction methods are used to approximate the
numerical discretization of a model in order to reduce the
computational cost of its simulation while staying faithful to the
full dynamics. To achieve this\, projection-based methods construct
a reduced basis from full simulation data and project the dynamics
onto the spanned linear subspace. For nonlinear problems\,
hyper-reduction methods are additionally needed to remove the
dependence of the nonlinear terms on the full problem’s size\,
completing the reduction process. In this work\, we develop an
energy conservative hyperreduction method for hydrodynamics PDE
problems discretized on a Lagrangian moving grid by high order
finite element methods. Based on an existing empirical quadrature
procedure\, our method employs sparse numerical quadrature rules to
estimate the model’s nonlinear integral terms with a chosen degree
of accuracy while ensuring that energy is conserved. We apply our
method to well established benchmark problems\, demonstrating that
it achieves superior energy conservation and similar accuracy and
computational speedup compared to the preexisting\, non-conservative
method.
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2004@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240307T132000
DTEND;TZID=America/New_York:20240307T142000
CATEGORIES:Geometry Seminar
SUMMARY:Corey Bregman: TBD
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2049@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240312T143000
DTEND;TZID=America/New_York:20240312T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Rachael Alfant: TBA
LOCATION:Zoom
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c208f@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240326T142500
DTEND;TZID=America/New_York:20240326T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Freddy Saia: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c20d5@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240326T143000
DTEND;TZID=America/New_York:20240326T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Wenjun Zhao: TBA
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c211a@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240328T151500
CATEGORIES:Math Colloquium
SUMMARY:Mason Porter: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/activities/colloquia/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2161@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240402T142500
DTEND;TZID=America/New_York:20240402T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Owen Biesel: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c21a7@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240402T143000
DTEND;TZID=America/New_York:20240402T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Asher Leeks: TBA
LOCATION:Zoom
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c21ec@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240409T142500
DTEND;TZID=America/New_York:20240409T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Juanita Duque-Rosero: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2232@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240409T143000
DTEND;TZID=America/New_York:20240409T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Erik Bates: TBA
LOCATION:Zoom
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2277@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240416T142500
DTEND;TZID=America/New_York:20240416T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Mohammad Javad Latifi: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c22bd@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240416T143000
DTEND;TZID=America/New_York:20240416T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Carlo Lucibello: TBA
LOCATION:Zoom
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2302@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240418T151500
CATEGORIES:Math Colloquium
SUMMARY:Tom Roby: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/activities/colloquia/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2348@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240423T142500
DTEND;TZID=America/New_York:20240423T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Laure Flapan: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c238e@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240425T103000
CATEGORIES:Thesis Defence
SUMMARY:Yixin (Kathy) Lin: Penney's game for permutations
LOCATION:TBD
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c23d4@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240425T151500
CATEGORIES:Math Colloquium
SUMMARY:Evrydiki Nestoridi: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/calendar/agenda-colloq.php
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c241a@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240430T142500
DTEND;TZID=America/New_York:20240430T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Isabel Vogt: TBA
LOCATION:Kemeny 343
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2461@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240502T151500
CATEGORIES:Math Colloquium
SUMMARY:Isabel Vogt: Interpolation problems for curves.
DESCRIPTION:The interpolation problem is one of the oldest in
mathematics. In its most broad form it asks: when can a curve of a
given type be passed through a given number of points? I'll survey
work on the interpolation problem from Euclid to the modern day\,
ending with recent joint work of mine with Eric Larson.
LOCATION:004 Kemeny Hall
URL:https://math.dartmouth.edu/calendar/agenda-colloq.php
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c24ac@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240507T142500
DTEND;TZID=America/New_York:20240507T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:James Hotchkiss: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2500@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240507T143000
DTEND;TZID=America/New_York:20240507T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Zeynep Ertem: TBA
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2545@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240514T142500
DTEND;TZID=America/New_York:20240514T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Alvaro Lozano-Robledo: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c258b@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240514T143000
DTEND;TZID=America/New_York:20240514T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:James Siderius: TBA
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c25d1@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240515T180000
CATEGORIES:⋆ Kemeny Lecture ⋆
SUMMARY:Anne Schilling: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/activities/kemeny-lectures/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c2617@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240516T151500
CATEGORIES:⋆ Kemeny Lecture ⋆
SUMMARY:Anne Schilling: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/activities/kemeny-lectures/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c265d@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240517T151500
CATEGORIES:⋆ Kemeny Lecture ⋆
SUMMARY:Anne Schilling: TBA
LOCATION:TBA
URL:https://math.dartmouth.edu/activities/kemeny-lectures/
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c26a3@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240521T142500
DTEND;TZID=America/New_York:20240521T152500
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:Lisa Marquand: TBD
LOCATION:Kemeny 343
URL:https://math.dartmouth.edu/~zahlen
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c26e9@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240521T143000
DTEND;TZID=America/New_York:20240521T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Kui Ren: TBA
LOCATION:Kemeny 307
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240222T114701Z
UID:20240222T06470165d73435c272e@math.dartmouth.edu
DTSTART;TZID=America/New_York:20240528T143000
DTEND;TZID=America/New_York:20240528T153000
CATEGORIES:Applied and Computational Mathematics Seminar
SUMMARY:Anton Bovier: TBA
LOCATION:Zoom
END:VEVENT
END:VCALENDAR