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BEGIN:VEVENT
SUMMARY:Alexander Ivanov (Ruhr-Universität Bochum)
DTSTART:20240923T200000Z
DTEND:20240923T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/1
DESCRIPTION:Title: p-adic Deligne--Lusztig spaces\nby Alexander Ivanov (Ruhr-Universi
tät Bochum) as part of Boston University Number Theory Seminar\n\nLecture
held in CDS Room 365 in Boston University.\n\nAbstract\nI explain how to
carry over some definitions and results from classical Deligne--Luzstig th
eory (for reductive groups over finite fields) to a setup over p-adic fiel
ds. More precisely\, I discuss p-adic Deligne--Lusztig spaces\, defined as
certain arc-sheaves on perfect algebras over the residue field\, as well
as some of their geometric properties. In some cases\, one can determine t
he cohomology of these spaces\, and use it to construct smooth representat
ions of p-adic reductive groups geometrically.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jerson Caro (Boston University)
DTSTART:20240909T200000Z
DTEND:20240909T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/2
DESCRIPTION:Title: Diophantine properties for the special values of Dedekind zeta functio
ns\nby Jerson Caro (Boston University) as part of Boston University Nu
mber Theory Seminar\n\nLecture held in CDS Room 365 in Boston University.\
n\nAbstract\nAccording to Nothcott's theorem\, any set of algebraic number
s of bounded height and bounded degree is finite. Analogous finiteness pro
perties are also satisfied by many other heights\, such as the Faltings he
ight. Given the many conjectural links between heights and special values
of L-functions (with the BSD conjecture as the most remarkable example)\,
it is natural to ask whether special values of L-functions satisfy a simil
ar Northcott property. In this talk\, we will outline joint work in progre
ss with Fabien Pazuki and Riccardo Pengo that shows the Northcott property
does not hold for the Dedekind zeta function at 1/2.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Bertoloni-Meli (Boston University)
DTSTART:20240916T200000Z
DTEND:20240916T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/3
DESCRIPTION:Title: The categorical conjecture and cuspidal sheaves\nby Alexander Bert
oloni-Meli (Boston University) as part of Boston University Number Theory
Seminar\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\
nI will discuss the categorical conjecture of Fargues and Scholze and desc
ribe work in progress with Teruhisa Koshikawa to explicate structures on t
he Galois side. In particular\, I will describe a category of cuspidal she
aves on the stack of L-parameters and show how it explicates some classica
l phenomena.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sameera Vemulapalli (Harvard University)
DTSTART:20240930T200000Z
DTEND:20240930T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/4
DESCRIPTION:Title: Steinitz classes of number fields and Tschirnhausen bundles of covers
of the projective line\nby Sameera Vemulapalli (Harvard University) as
part of Boston University Number Theory Seminar\n\nLecture held in CDS Ro
om 365 in Boston University.\n\nAbstract\nGiven a number field extension $
L/K$ of fixed degree\, one may consider $\\mathcal{O}_L$ as an $\\mathcal{
O}_K$-module. Which modules arise this way? Analogously\, in the geometric
setting\, a cover of the complex projective line by a smooth curve yields
a vector bundle on the projective line by pushforward of the structure sh
eaf\; which bundles arise this way? In this talk\, I'll describe recent wo
rk with Vakil in which we use tools in arithmetic statistics (in particula
r\, binary forms) to completely answer the first question and make progres
s towards the second.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Colby Brown (UC Davis)
DTSTART:20241007T200000Z
DTEND:20241007T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/5
DESCRIPTION:Title: An almost linear time algorithm testing whether the Markoff graph modu
lo $p$ is connected\nby Colby Brown (UC Davis) as part of Boston Unive
rsity Number Theory Seminar\n\nLecture held in CDS Room 365 in Boston Univ
ersity.\n\nAbstract\nThe Markoff graph modulo p is known to be connected f
or all but finitely many primes p (see Eddy\, Fuchs\, Litman\, Martin\, Tr
ipeny\, and Vanyo [arXiv:2308.07579])\, and it is conjectured that these g
raphs are connected for all primes. In this talk\, we outline an algorithm
ic realization of the process introduced by Bourgain\, Gamburd\, and Sarna
k [arXiv:1607.01530] to test whether the Markoff graph modulo p is connect
ed for arbitrary primes. Our algorithm runs in o(p1+ϵ) time for every ϵ>
0. Our algorithm confirms that the Markoff graph modulo p is connected for
all primes less than one million.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rob Benedetto (Amherst College)
DTSTART:20241021T200000Z
DTEND:20241021T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/6
DESCRIPTION:Title: Arboreal Galois groups with colliding critical points\nby Rob Bene
detto (Amherst College) as part of Boston University Number Theory Seminar
\n\nLecture held in CDS Room 548 in Boston University (*NOT the usual room
for the semester*).\n\nAbstract\nLet $f\\in K(z)$ be a rational function
of degree $d\\geq 2$ defined over a field $K$ (usually $\\mathbb{Q}$)\, an
d let $x_0\\in K$. The backward orbit of $x_0$\, which is the union of the
iterated preimages $f^{-n}(x_0)$\, has the natural structure of a $d$-ary
rooted tree. Thus\, the Galois groups of the fields generated by roots of
the equations $f^n(z)=x_0$ are known as arboreal Galois groups. In 2013\,
Pink observed that when $d=2$ and the two critical points $c_1\,c_2$ of $
f$ collide\, meaning that $f^m(c_1)=f^m(c_2)$ for some $m\\geq 1$\, then t
he arboreal Galois groups are strictly smaller than the full automorphism
group of the tree. We study these arboreal Galois groups when $K$ is a num
ber field and $f$ is either a quadratic rational function (as in Pink's se
tting over function fields) or a cubic polynomial with colliding critical
points. We describe the maximum possible Galois groups in these cases\, an
d we present sufficient conditions for these maximum groups to be attained
.\n\nJoint BU Number Theory and Dynamics seminar. Note the non-standard ro
om.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matt Broe (Boston University)
DTSTART:20241028T200000Z
DTEND:20241028T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/7
DESCRIPTION:Title: The Tate conjecture for a power of a CM elliptic curve\nby Matt Br
oe (Boston University) as part of Boston University Number Theory Seminar\
n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nThe end
omorphisms of an abelian variety $A$ over a field $k$ induce a natural dec
omposition of the Chow motive of $A$. For $E$ an elliptic curve over $k$ w
ith complex multiplication\, we explicitly describe the decomposition of t
he motive of $E^g$. When $k$ is finitely generated\, we use the decomposit
ion to prove the full Tate conjecture for $E^g$. When $k$ is a global func
tion field\, we formulate a version of the Beilinson-Bloch conjecture for
varieties over $k$ and prove it in some special cases\, including for powe
rs of an isotrivial elliptic curve with all its endomorphisms defined over
$k$.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cecilia Salgado (University of Groningen and IAS)
DTSTART:20241104T210000Z
DTEND:20241104T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/8
DESCRIPTION:Title: Mordell-Weil rank jumps on families of elliptic curves\nby Cecilia
Salgado (University of Groningen and IAS) as part of Boston University Nu
mber Theory Seminar\n\nLecture held in CDS Room 365 in Boston University.\
n\nAbstract\nWe will present some recent developments around the variation
of the Mordell-Weil rank in 1-dimensional families of elliptic curves\, b
y studying them in the guise of elliptic surfaces. We will revisit Néron-
Shioda's construction of an infinite family of elliptic curves with rank a
t least 11 and discuss ways of generalizing it.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sheela Devadas
DTSTART:20241111T210000Z
DTEND:20241111T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/9
DESCRIPTION:Title: Higher-weight Jacobians for complex varieties of maximal Picard number
\nby Sheela Devadas as part of Boston University Number Theory Seminar
\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nThis t
alk is about my work with Max Lieblich where we define and study Jacobians
of Hodge structures with weight greater than 1. Jacobians of weight 2 or
"2-Jacobians" naturally come up in the context of the Brauer group and the
Tate conjecture\, and were previously studied in a special case by Beauvi
lle in his work on surfaces of maximal Picard number. I will explain how w
e compute higher-weight Jacobians (as complex tori) for certain special cl
asses of complex varieties\, namely abelian varieties of maximal Picard ra
nk or singular K3 surfaces. Surprisingly\, these $m$-Jacobians are algebra
ic for all values of $m$.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Linli Shi (University of Connecticut)
DTSTART:20241118T210000Z
DTEND:20241118T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/10
DESCRIPTION:Title: On higher regulators of Picard modular surfaces\nby Linli Shi (Un
iversity of Connecticut) as part of Boston University Number Theory Semina
r\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nThe B
irch and Swinnerton-Dyer conjecture relates the leading coefficient of the
L-function of an elliptic curve at its central critical point to global a
rithmetic invariants of the elliptic curve. Beilinson’s conjectures gene
ralize the BSD conjecture to formulas for values of motivic L-functions at
non-critical points. In this talk\, I will relate motivic cohomology clas
ses\, with non-trivial coefficients\, of Picard modular surfaces to a non-
critical value of the motivic L-function of certain automorphic representa
tions of the group GU(2\,1).\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Linus Hamann (Harvard University)
DTSTART:20241125T210000Z
DTEND:20241125T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/11
DESCRIPTION:Title: Shimura Varieties and Eigensheaves\nby Linus Hamann (Harvard Univ
ersity) as part of Boston University Number Theory Seminar\n\nLecture held
in CDS Room 365 in Boston University.\n\nAbstract\nThe cohomology of Shim
ura varieties is a fundamental object of study in algebraic number theory
by virtue of the fact that it is the only known geometric realization of t
he global Langlands correspondence over number fields. Usually\, the cohom
ology is computed through very delicate techniques involving the trace for
mula. However\, this perspective has several limitations\, especially with
regards to questions concerning torsion. In this talk\, we will discuss
a new paradigm for computing the cohomology of Shimura varieties by decomp
osing certain sheaves coming from Igusa varieties into Hecke eigensheaves
on the moduli stack of G-bundles on the Fargues-Fontaine curve. Using this
point of view\, we will describe several conjectures on the torsion cohom
ology of Shimura varieties after localizing at suitably “generic” L-pa
rameters\, as well as some known results in the case that the parameter fa
ctors through a maximal torus. Motivated by this\, we will sketch part of
an emerging picture for describing the cohomology beyond this generic locu
s by considering certain “generalized eigensheaves” whose eigenvalues
are spread out in multiple cohomological degrees based on the size of a ce
rtain Arthur SL_{2} in a way that is reminiscent of Arthur’s cohomologic
al conjectures on the intersection cohomology of Shimura Varieties. This i
s based on joint work with Lee\, joint work in progress with Caraiani and
Zhang\, and conversations with Bertoloni-Meli and Koshikawa.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:TBA
DTSTART:20241202T210000Z
DTEND:20241202T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/12
DESCRIPTION:by TBA as part of Boston University Number Theory Seminar\n\nL
ecture held in CDS Room 365 in Boston University.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Patrick Daniels (Skidmore College)
DTSTART:20241209T210000Z
DTEND:20241209T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/13
DESCRIPTION:Title: Igusa Stacks and the Cohomology of Shimura Varieties\nby Patrick
Daniels (Skidmore College) as part of Boston University Number Theory Semi
nar\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nSch
olze has conjectured that there should exist an “Igusa stack” which in
terpolates between the various Igusa varieties associated with a given Shi
mura variety. In this talk\, we will motivate the Igusa stack conjecture a
nd report on recent progress on the conjecture in the Hodge-type case. If
time permits\, we will discuss some of the (many) consequences of the conj
ecture for the study of the cohomology of Shimura varieties. Everything we
will discuss is from joint work with Pol van Hoften\, Dongryul Kim\, and
Mingjia Zhang.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arnaud Eteve (MPIM)
DTSTART:20250324T200000Z
DTEND:20250324T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/15
DESCRIPTION:Title: Spectral action on isocrystals\nby Arnaud Eteve (MPIM) as part of
Boston University Number Theory Seminar\n\nLecture held in CDS Room 365 i
n Boston University.\n\nAbstract\nThis is joint work in progress with Denn
is Gaitsgory\, Alain Genestier and Vincent Lafforgue. Let $G$ be a reducti
ve group over a local function field $F$. In their seminal work\, Fargues
and Scholze proposed a geometrization of the local Langlands correspondanc
e for the pair $(G\,F)$ by constructing a 'spectral action' on the categor
y of $\\ell$-adic sheaves on $\\mathrm{Bun}_G$\, the stack of $G$-torsors
on the Fargues-Fontaine curve. The goal of this talk is to explain the con
struction of a different spectral action on the category of sheaves on the
stack of $G$-isocrystals which should offer another geometrization of the
local Langlands correspondance. Our construction has the benefit of being
naturally compatible with the announced work of Hemo and Zhu and should a
lso be equipped with a strong form of local-global compatibility.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jerson Caro (Boston University)
DTSTART:20250127T210000Z
DTEND:20250127T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/16
DESCRIPTION:Title: Rational points: Curves and beyond\nby Jerson Caro (Boston Univer
sity) as part of Boston University Number Theory Seminar\n\nLecture held i
n CDS Room 365 in Boston University.\n\nAbstract\nIn 1985\, Coleman\, buil
ding on Chabauty's work from 1941\, established an upper bound for the num
ber of rational points of curves satisfying certain conditions. In this ta
lk\, I will present the first generalization of this method to higher dime
nsions\, specifically to the case of surfaces. This is joint work with Hec
tor Pasten. Furthermore\, I will discuss recent work with Jennifer Balakri
shnan\, in which we provide explicit examples of surfaces that demonstrate
the effectiveness of the method developed by H. Pasten and me. Specifical
ly\, we show that there are surfaces for which the obtained bound is sharp
.\n\nFinally\, I will present joint work with Natalia García-Fritz\, wher
e we prove that a certain family of surfaces has a uniformly bounded numbe
r of rational points. In other words\, the same upper bound applies to all
surfaces in the family.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nina Zubrilina (MIT)
DTSTART:20250203T210000Z
DTEND:20250203T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/17
DESCRIPTION:Title: Root Number Correlation Bias of Fourier Coefficients of Modular Forms
\nby Nina Zubrilina (MIT) as part of Boston University Number Theory S
eminar\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\n
In a recent study\, He\, Lee\, Oliver\, and Pozdnyakov observed a striking
oscillating pattern in the average value of the P-th Frobenius trace of e
lliptic curves of prescribed rank and conductor in an interval range. Suth
erland discovered that this bias extends to Dirichlet coefficients of a mu
ch broader class of arithmetic L-functions when split by rootnumber.\n In
my talk\, I will discuss this root numbercorrelation in families of holomo
rphic and Maass forms.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:TBA
DTSTART:20250210T210000Z
DTEND:20250210T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/18
DESCRIPTION:by TBA as part of Boston University Number Theory Seminar\n\nL
ecture held in CDS Room 365 in Boston University.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Candace Bethea (Brown University)
DTSTART:20250224T210000Z
DTEND:20250224T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/19
DESCRIPTION:Title: Counting rational curves equivariantly\nby Candace Bethea (Brown
University) as part of Boston University Number Theory Seminar\n\nLecture
held in CDS Room 365 in Boston University.\n\nAbstract\nThis talk will be
a friendly introduction to using topological invariants in enumerative geo
metry and how one might use equivariant homotopy theory to answer enumerat
ive questions under the presence of a finite group action. Recent work wit
h Kirsten Wickelgren (Duke) defines a global and local degree in stable eq
uivariant homotopy theory that can be used to compute the equivariant Eule
r characteristic and Euler number. I will discuss an application to counti
ng orbits of rational plane cubics through an invariant set of 8 points in
general position under a finite group action on $\\mathbb{C}\\mathbb{P}^2
$\, valued in the representation ring and Burnside ring. This recovers a s
igned count of real rational cubics when $\\mathbb{Z}/2$ acts on $\\mathbb
{C}\\mathbb{P}^2$ by complex conjugation.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rahul Dalal (University of Vienna)
DTSTART:20250303T210000Z
DTEND:20250303T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/20
DESCRIPTION:Title: Automorphic Representations and Quantum Logic Gates\nby Rahul Dal
al (University of Vienna) as part of Boston University Number Theory Semin
ar\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nAny
construction of a quantum computer requires finding a good set of universa
l quantum logic gates: abstractly\, a finite set of matrices in U(2^n) suc
h that short products of them can efficiently approximate arbitrary unitar
y transformations. The 2-qubit case n=2 is of particular practical interes
t. I will present the first construction of an optimal\, so-called "golden
" set of 2-qubit gates. \n\nThe modern theory of automorphic representatio
ns on unitary groups---in particular\, the endoscopic classification and h
igher-rank versions of the Ramanujan bound---will play a crucial role in p
roving the necessary analytic estimates.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eran Assaf (MIT)
DTSTART:20250331T200000Z
DTEND:20250331T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/22
DESCRIPTION:Title: Orthogonal modular forms from definite quaternary lattices\nby Er
an Assaf (MIT) as part of Boston University Number Theory Seminar\n\nLectu
re held in CDS Room 365 in Boston University.\n\nAbstract\nIn this talk I
will make precise the fact that definite quaternary orthogonal modular for
ms are Hilbert modular forms. By taking the algebraic approach and using t
he Clifford functor\, we can avoid analytic difficulties in the theta lift
s\, and give a precise description of level and character on both sides of
the transfer map. Building on advancements in our understanding of orders
in quaternion algebras\, we are able to apply this result to a large clas
s of lattices\, allowing for singularities of high codimension. \nThis is
joint work with Dan Fretwell\, Adam Logan\, Colin Ingalls\, Spencer Secord
and John Voight.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alice Lin (Harvard University)
DTSTART:20250407T200000Z
DTEND:20250407T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/23
DESCRIPTION:Title: Shafarevich's conjecture for families of hypersurfaces over function
fields\nby Alice Lin (Harvard University) as part of Boston University
Number Theory Seminar\n\nLecture held in CDS Room 365 in Boston Universit
y.\n\nAbstract\nShafarevich's conjecture suggests that over a fixed base s
cheme $B$\, whether it is the $S$-integers of a number field or a quasipro
jective variety\, there should be only finitely many nonisotrivial familie
s of projective varieties of a given type over $B$. For example\, in provi
ng the Mordell Conjecture\, Faltings proved that there are only finitely m
any families of principally polarized abelian schemes of a given dimension
over the $S$-integers of a number field. We prove a Shafarevich conjectur
e for Hodge-generic families of hypersurfaces for sufficiently large degre
e and dimension over a complex quasiprojective base. The argument follows
a "boundedness and rigidity" structure to show that the space of such fami
lies is finite. For boundedness\, the key input is a new result of Bakker\
, Brunebarbe\, and Tsimerman about the ampleness of the Griffiths line bun
dle for quasifinite period mappings. For rigidity\, we use a Hodge-theoret
ic formulation due to Peters.\n\nThis is joint work with Philip Engel and
Salim Tayou.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vasily Dolgushev (Temple University)
DTSTART:20250414T200000Z
DTEND:20250414T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/24
DESCRIPTION:Title: Exploration of Grothendieck-Teichmueller (GT) shadows\nby Vasily
Dolgushev (Temple University) as part of Boston University Number Theory S
eminar\n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\n
In 1990\, V. Drinfeld introduced the Grothendieck-Teichmueller group GT.\n
This mysterious group receives a homomorphism from the absolute Galois gro
up $G_Q$\nof rational numbers\, and this homomorphism is injective due to
Belyi's theorem. \nGrothendieck-Teichmueller (GT) shadows may be thought o
f as approximations \nof elements of the group GT. They are morphisms of a
groupoid whose objects are \ncertain finite index normal subgroups of the
Artin braid group. Exploration of the \ngroupoid of GT-shadows is motivat
ed by very hard open problems that include \nY. Ihara's question about the
surjectivity of the homomorphism from $G_Q$ to GT.\nIn my talk\, I will i
ntroduce the groupoid of GT-shadows and describe \nits relation to the gro
up GT. I will also present promising results \nand formulate selected open
problems. My talk is loosely based on joint papers \nwith I. Bortnovskyi\
, J.J. Guynee\, B. Holikov and V. Pashkovskyi.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hao Peng (MIT)
DTSTART:20250428T200000Z
DTEND:20250428T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/25
DESCRIPTION:Title: Fargues-Scholze vs. classical parameters\, and applications\nby H
ao Peng (MIT) as part of Boston University Number Theory Seminar\n\nLectur
e held in CDS Room 365 in Boston University.\n\nAbstract\nFor general redu
ctive groups over a $p$-adic local field\, Fargues and Scholze constructed
a (semi-simplified) local Langlands with many good properties. On the oth
er hand\, classical local Langlands correspondences are known for classica
l groups via endoscopy theory and theta lifting. We review the constructio
n of Fargues-Scholze and related geometric objects\, and prove these two c
orrespondences are compatible for all unramified special orthogonal and un
itary groups. As an application\, we prove torsion vanishing results for o
rthogonal Shimura varieties\, generalizing results of Caraiani-Scholze\, K
oshikawa\, Santos and Hamann-Lee\, etc.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Leonhardt (Boston University)
DTSTART:20250908T200000Z
DTEND:20250908T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/26
DESCRIPTION:Title: The affine Chabauty method\nby Marius Leonhardt (Boston Universit
y) as part of Boston University Number Theory Seminar\n\nLecture held in C
DS Room 548 in Boston University.\n\nAbstract\nGiven a hyperbolic curve $Y
$ defined over the integers and a finite set of primes $S$\, the set of $S
$-integral points $Y(\\mathbb{Z}_S)$ is finite by theorems of Siegel\, Mah
ler\, and Faltings. Determining this set in practice is a difficult proble
m for which no general method is known. In this talk I report on joint wor
k in progress with Martin Lüdtke in which we develop a Chabauty--Coleman
method for finding $S$-integral points on affine curves. We achieve this b
y bounding the image of $Y(\\mathbb{Z}_S)$ in the Mordell--Weil group of t
he generalised Jacobian using arithmetic intersection theory on a regular
model.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sachi Hashimoto (Brown University)
DTSTART:20250915T200000Z
DTEND:20250915T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/27
DESCRIPTION:Title: Rational points on $X_0(N)^∗$ when $N$ is non-squarefree\nby Sa
chi Hashimoto (Brown University) as part of Boston University Number Theor
y Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\nAbstrac
t\nThe rational points of the modular curve $X_0(N)$ classify pairs $(E\,C
_N)$ of elliptic curves over $\\mathbb{Q}$ together with a rational cyclic
subgroup of order $N$. The curve $X_0(N)^∗$ is the quotient of $X_0(N)$
by the full group of Atkin-Lehner involutions. Elkies showed that the rat
ional points on this curve classify elliptic curves over the algebraic clo
sure of $\\mathbb{Q}$ that are isogenous to their Galois conjugates\, and
conjectured that when $N$ is large enough\, the points are all CM or cuspi
dal. In joint work with Timo Keller and Samuel Le Fourn\, we study the rat
ional points on the family $X_0(N)^∗$ for $N$ non-squarefree. In particu
lar we will report on some integrality results for the j-invariants of poi
nts on $X_0(N)^∗$.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jit Wu Yap (MIT)
DTSTART:20250922T200000Z
DTEND:20250922T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/28
DESCRIPTION:Title: On Uniform Boundedness of Torsion Points for Abelian Varieties over F
unction Fields\nby Jit Wu Yap (MIT) as part of Boston University Numbe
r Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\n
Abstract\nLet $K$ be the function field of a smooth projective curve $B$ o
ver the complex numbers and let $g$ be a positive integer. The uniform bou
ndedness conjecture predicts that there exists a constant $N$\, depending
only on $g$ and $K$\, such that for any $g$-dimensional abelian variety $A
$ over $K$\, any $K$-rational torsion point of $A$ must have order at most
$N$. In this talk\, we will discuss some recent progress under the assump
tion that $A$ has semistable reduction over $K$. This is joint work with N
icole Looper.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Isabel Rendell (King's College London)
DTSTART:20250929T200000Z
DTEND:20250929T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/29
DESCRIPTION:Title: Quadratic Chabauty for Atkin-Lehner quotients of modular curves via w
eakly holomorphic modular forms\nby Isabel Rendell (King's College Lon
don) as part of Boston University Number Theory Seminar\n\nLecture held in
CDS Room 548 in Boston University.\n\nAbstract\nQuadratic Chabauty is a m
ethod to explicitly compute the rational points on certain modular curves
of genus at least 2. The current algorithm\, due to Balakrishnan-Dogra-Mü
ller-Tuitman-Vonk\, requires as an input an explicit plane model of the cu
rve. The coefficients of such models grow rapidly with the genus of the cu
rve and so are inefficient to compute with when the genus is at least 7. T
herefore\, we would like to replace this input with certain modular forms
associated to the curve\, hence creating a 'model-free' algorithm. In this
talk I will provide an overview of an algorithm to compute the first stag
e of quadratic Chabauty on Atkin-Lehner quotients of modular curves using
weakly holomorphic modular forms.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jerson Caro (Boston University)
DTSTART:20251006T200000Z
DTEND:20251006T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/30
DESCRIPTION:Title: On the Visibility category of elements in the Shafarevich-Tate group<
/a>\nby Jerson Caro (Boston University) as part of Boston University Numbe
r Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\n
Abstract\nGiven an elliptic curve over Q and a nontrivial element sigma of
its Shafarevich--Tate group Sha(E)\, we introduce the *Visualization cate
gory* of abelian varieties that ``visualize'' sigma\, in the sense of Crem
ona--Mazur\, and we study minimal objects in this category\, furnishing ex
amples of their nonuniqueness. In particular\, we show that there can be s
everal minimal visualizing abelian varieties of different dimensions\, ans
wering a question of Mazur. This is joint work with Barinder Banwait and S
hiva Chidambaram.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kate Finnerty (Boston University)
DTSTART:20251020T200000Z
DTEND:20251020T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/31
DESCRIPTION:Title: On the possible adelic indices of certain families of elliptic curves
\nby Kate Finnerty (Boston University) as part of Boston University Nu
mber Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\
n\nAbstract\nA well-known theorem of Serre bounds the largest prime $\\ell
$ for which the mod $\\ell$ Galois representation of a non-CM elliptic cur
ve $E/\\mathbb{Q}$ is nonsurjective. Serre asked whether a universal bound
on the largest nonsurjective prime might exist. Significant partial progr
ess has been made toward this question. Lemos proved that it has an affirm
ative answer for all $E$ admitting a rational cyclic isogeny. Zywina offer
ed a more ambitious conjecture about the possible adelic indices that can
occur as $E$ varies. We will discuss an ongoing project (joint with Tyler
Genao\, Jacob Mayle\, and Rakvi) that extends Lemos's result to prove Zywi
na's conjecture for certain families of elliptic curves.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Casimir Kothari (University of Chicago)
DTSTART:20251027T200000Z
DTEND:20251027T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/32
DESCRIPTION:Title: Dieudonné theory for $n$-smooth group schemes\nby Casimir Kothar
i (University of Chicago) as part of Boston University Number Theory Semin
ar\n\nLecture held in CDS Room 548 in Boston University.\n\nAbstract\nDieu
donné theory is the study of families of group schemes via linear-algebra
ic data. In this talk\, I will begin by recalling some motivation for Di
eudonné theory\, with examples. Then I will explain some new classifica
tion and smoothness results for certain close relatives of $p$-divisible g
roups known as $n$-smooth groups\, which affirmatively answer conjectures
of Drinfeld. This is joint work with Joshua Mundinger.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeff Achter (Colorado State University)
DTSTART:20251103T210000Z
DTEND:20251103T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/33
DESCRIPTION:Title: Regular homomorphisms\, with a twist\nby Jeff Achter (Colorado St
ate University) as part of Boston University Number Theory Seminar\n\nLect
ure held in CDS Room 548 in Boston University.\n\nAbstract\nLet $X$ be a s
mooth projective variety over a field. If the field is $\\mathbb C$\, Gri
ffiths associates to $X$ an algebraic intermediate Jacobian $J$\, which is
a complex abelian variety which captures some information about pointed f
amilies of algebraic cycles on $X$. More generally\, a regular homomorphi
sm to an abelian variety accomplishes something similar for pointed famili
es of algebraic\ncycles on a variety over any perfect field.\n\nFor famili
es of cycles which don't admit a point over the field of\ndefinition\, we
obtain instead a map to a torsor under that abelian\nvariety. I'll explai
n these results and what they tell us about the\nrationality of certain th
reefolds. (Joint work with Sebastian\nCasalaina-Martin and Charles Vial
.)\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jialiang Zou (MIT)
DTSTART:20251110T210000Z
DTEND:20251110T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/34
DESCRIPTION:Title: Theta correspondence and Springer correspondence\nby Jialiang Zou
(MIT) as part of Boston University Number Theory Seminar\n\nLecture held
in CDS Room 365 in Boston University.\n\nAbstract\nLet V and W be an ortho
gonal and a symplectic space\, respectively. The action of G=O(V)\\times S
p(W) on V\\otimes W provides an example of G-hyperspherical varieties intr
oduced by D. Ben-Zvi\, Y. Sakellaridis\, and A. Venkatesh (BZSV for short)
. It is the classical limit of theta correspondence from the perspective o
f quantization.. I will explain a geometric construction motivated by thet
a correspondence over finite fields\, which describes how principal series
representations behave under theta correspondence using Springer correspo
ndence. \n\nBZSV proposed a relative Langlands duality linking certain G-h
yperspherical varieties M with their dual G^\\vee-hyperspherical varieties
M^\\vee. A remarkable instance of this duality is that the hyperspherical
variety underlying theta correspondence is dual to the hyperspherical var
iety underlying the branching problem in the Gan-Gross-Prasad conjecture.
I will discuss how these results fit into the broader framework of this r
elative Langlands duality. This is an ongoing joint work with Jiajun Ma\,
Congling Qiu\, and Zhiwei Yun.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ananth Shankar (Northwestern University)
DTSTART:20251117T210000Z
DTEND:20251117T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/35
DESCRIPTION:Title: $p$-adic hyperbolicity for Shimura varieties and period images\nb
y Ananth Shankar (Northwestern University) as part of Boston University Nu
mber Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\
n\nAbstract\nBorel proved that every holomorphic map from a product of pun
ctured unit discs to a complex Shimura variety extends to a map from a pro
duct of discs to its Bailey-Borel compactification. In joint work with Osw
al\, Zhu\, and Patel\, we proved a p-adic version of this theorem over dis
cretely valued fields for Shimura varieties of abelian type. I will speak
about work with Bakker\, Oswal\, and Yao\, where we prove the analogous $p
$-adic extension theorem for compact non-abelian Shimura varieties and geo
metric period images for large primes $p$.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jane Shi (MIT)
DTSTART:20251124T210000Z
DTEND:20251124T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/36
DESCRIPTION:Title: Lifting $L$-polynomials of genus 2 curves\nby Jane Shi (MIT) as p
art of Boston University Number Theory Seminar\n\nLecture held in CDS Room
548 in Boston University.\n\nAbstract\nLet $C$ be a genus $2$ curve over
$\\mathbb{Q}$. For each odd prime $p$\nof good reduction\, we denote the n
umerator \nof the zeta function of $C$ at $p$ by $L_p(T)$.\n\nHarvey and S
utherland's \nimplementation of Harvey's average polynomial-time algorithm
computes \n$L_p(T) \\bmod \\ p$ for all good primes $p\\leq B$ in $O(B\\l
og^{3+o(1)}B)$ time\, which is \n$O(\\log^{4+o(1)} p)$ time on average per
prime.\nAlternatively\, their algorithm can do this for a single good pri
me \n$p$ in $O(p^{1/2}\\log^{1+o(1)}p)$ time. While Harvey's algorithm \nc
an also be used to compute the full zeta function\, no practical implement
ation \nof this step currently exists.\n\n\nIn this talk\, I will present
an $O(\\log^{2+o(1)}p)$ Las Vegas algorithm that \ntakes the $\\bmod \\ p$
output of Harvey and Sutherland's implementation and \ncomputes the full
zeta function. I will also show benchmark results \ndemonstrating substant
ial speedups compared to the fastest\nalgorithms currently available for c
omputing the full zeta function of a genus $2$ curve.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fangu Chen (UC Berkeley)
DTSTART:20251201T210000Z
DTEND:20251201T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/37
DESCRIPTION:Title: A generalization of Elkies’ theorem on infinitely many supersingula
r primes\nby Fangu Chen (UC Berkeley) as part of Boston University Num
ber Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\n
\nAbstract\nIn 1987\, Elkies proved that every elliptic curve defined over
$\\mathbb{Q}$ has infinitely many supersingular primes. In this talk\, I
will present an extension of this result to certain abelian fourfolds in M
umford’s families and more generally\, to some Kuga-Satake abelian varie
ties constructed from K3-type Hodge structures with real multiplication. I
will review Elkies’ proof and explain how his strategy of intersecting
with CM cycles can be adapted to our setting. I will also discuss some of
the techniques in our proof to study the local properties of the CM cycles
.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Obus (Baruch College)
DTSTART:20251208T210000Z
DTEND:20251208T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/38
DESCRIPTION:Title: Regular models of superelliptic curves via Mac Lane valuations\nb
y Andrew Obus (Baruch College) as part of Boston University Number Theory
Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\nAbstract\
nLet $X \\rightarrow \\mathbb{P}^1$ be a $\\mathbb{Z}/n$-branched cover ov
er a complete discretely valued field $K$\, where $n$ does not divide the
residue characteristic of $K$. We explicitly construct the minimal regula
r normal crossings model of $X$ over the valuation ring of $K$. By “exp
licitly”\, we mean that we construct a normal model of $\\mathbb{P}^1$ w
hose normalization in $K(X)$ is the desired regular model. The normal mod
el of $\\mathbb{P}^1$ is fully encoded as a basket of finitely many discre
te valuations on the rational function field $K(\\mathbb{P}^1)$\, each of
which is given using Mac Lane’s 1936 notation involving finitely many po
lynomials and rational numbers. This is joint work with Padmavathi Sriniv
asan.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amnon Besser (Ben Gurion University)
DTSTART:20260202T210000Z
DTEND:20260202T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/40
DESCRIPTION:Title: On the Katz-Litt Theorem\nby Amnon Besser (Ben Gurion University)
as part of Boston University Number Theory Seminar\n\nLecture held in CDS
Room 548 in Boston University.\n\nAbstract\nThe Katz-Litt theorem gives a
n explicit recipe to describe Vologodsky integration on curves with semi-s
table reduction in terms of Coleman integration on on the rigid analytic d
omains reducing to the smooth components of the reduction. In work with Mu
eller and Srinivasan we gave an alternative recipe\, more closely related
to our past work with Zerbes\, which was proved to follow from the Katz-Li
tt theorem by Katz. In this talk I will describe this alternative recipe a
nd prove it directly. This new proof is significantly simpler than the ori
ginal proof.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antoine de Saint Germain (University of Hong Kong)
DTSTART:20260209T210000Z
DTEND:20260209T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/41
DESCRIPTION:Title: Mordell-Schinzel surfaces and cluster algebras\nby Antoine de Sai
nt Germain (University of Hong Kong) as part of Boston University Number T
heory Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\nAbs
tract\nThe set of positive integer points of the celebrated Markov surface
admits the structure of a 3-regular tree. \n\nMy objective in this talk i
s to unveil a similar phenomenon for Mordell-Schinzel surfaces\; namely th
at the set of positive integer points of each such surface admits the stru
cture of a 2-regular graph. The vertices of each graph naturally correspon
d to clusters in a suitable (generalised) cluster algebra. \n\nI will then
explain how the structure theory of cluster algebras translates into a re
solution of the positive Mordell-Schinzel problem. \n\nThis is partly base
d on ongoing joint work with Robin Zhang (MIT).\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ilya Volkovich (Boston College)
DTSTART:20260223T210000Z
DTEND:20260223T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/42
DESCRIPTION:Title: A Computational Perspective on Carmichael Numbers\nby Ilya Volkov
ich (Boston College) as part of Boston University Number Theory Seminar\n\
nLecture held in CDS Room 548 in Boston University.\n\nAbstract\nWe consid
er the problem of deterministically factoring integers provided with oracl
e access to important number-theoretic functions such as Euler's Totient f
unction - $\\Phi(\\cdot)$ and Carmichael's Lambda function - $\\Lambda(\\c
dot)$.\nWe focus on Carmichael numbers - also known as Fermat pseudoprimes
. In particular\, we obtain the following results: \n\n1. Let $N$ be a `si
mple' Carmichael number with three prime factors (also known as simple $C_
3$-numbers). Then\, given oracle access to $\\lambda(\\cdot)$\, we can com
pletely factor $N$ in deterministic polynomial time.\n\n2. There exists a
deterministic polynomial-time algorithm that given oracle access to $\\Phi
(\\cdot)$\, completely factors simple $C_3$-numbers\, satisfying some `siz
e' bounds. Although in this case our methods do not provide a theoretical
guarantee for all such numbers due to the required size bounds\, we show e
xperimentally that our algorithm can factor more than 99\\% of all simple
$C_3$-numbers up to $10^{13}$.\n\n\nOur techniques extend the work of Mora
in\, Renault\, and Smith (Applicable\nAlgebra in Engineering\, Communicati
on\, and Computation\, 2023)\, at the core of which sits the Coppersmith's
method that provides an efficient way to find bounded roots of a bivariat
e polynomial over the integers. We combine these techniques with a new upp
er bound on $\\gcd(N-1\, \\Phi(N))$ for $C_3$-numbers\, which could be of
an independent interest.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jacksyn Bakeberg (Boston University)
DTSTART:20260302T210000Z
DTEND:20260302T220000Z
DTSTAMP:20260404T094751Z
UID:NTBU/43
DESCRIPTION:Title: Excursion functions on $p$-adic $\\mathrm{SL}_2$\nby Jacksyn Bake
berg (Boston University) as part of Boston University Number Theory Semina
r\n\nLecture held in CDS Room 548 in Boston University.\n\nAbstract\nThe B
ernstein center of a $p$-adic group is a commutative ring of certain distr
ibutions on the group\, and it interacts closely with the group’s repres
entation theory. Fargues and Scholze provide an abstract construction of a
class of elements of the Bernstein center called excursion operators\, wh
ich encode a candidate for the (semisimplified) local Langlands correspond
ence. In this talk\, I will present an approach to understanding excursion
operators concretely as distributions on the group\, with a special empha
sis on the case of $G = \\mathrm{SL}_2$ where everything can be made quite
explicit.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Schwein (University of Utah)
DTSTART:20260316T200000Z
DTEND:20260316T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/44
DESCRIPTION:Title: New supercuspidal representations from the Weil representation in cha
racteristic two\nby David Schwein (University of Utah) as part of Bost
on University Number Theory Seminar\n\nLecture held in CDS Room 548 in Bos
ton University.\n\nAbstract\nSupercuspidal representations are the mysteri
ous "elementary particles" from which all other representations of a reduc
tive p-adic group are built. Residue characteristic two presents additiona
l difficulties in the construction of these representations\, and even for
classical groups\, our knowledge is incomplete. In this talk\, based on j
oint work with Jessica Fintzen\, I'll explain how to overcome one of these
difficulties: the exceptional behavior of the Heisenberg group and Weil r
epresentation in characteristic two. Time permitting\, I'll also explain h
ow to overcome a second difficulty: disconnected Lie-algebra centralizers.
\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shiva Chidambaram (University of Wisconsin\, Madison)
DTSTART:20260323T200000Z
DTEND:20260323T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/45
DESCRIPTION:Title: Abelian threefolds with imaginary multiplication\, and elliptic curve
s attached to them\nby Shiva Chidambaram (University of Wisconsin\, Ma
dison) as part of Boston University Number Theory Seminar\n\nLecture held
in CDS Room 548 in Boston University.\n\nAbstract\nIt is an interesting pr
oblem to construct algebraic curves whose Jacobians have extra endomorphis
ms. When genus is 3\, there are two natural families of Jacobians with ima
ginary multiplication by $\\mathbb{Z}[i]$ and $\\mathbb{Z}[\\zeta_3]$\, co
ming from curves with a $\\mu_4$ or $\\mu_6$ action. We will report on new
hyperelliptic families with imaginary multiplication by $\\mathbb{Z}[\\sq
rt{-d}]$ for $d=2\,3\,4$\, and some instances of extending to any odd genu
s g. Galois representations allow one to naturally attach a CM elliptic cu
rve to any abelian threefold with imaginary multiplication of signature (2
\,1). For the new families\, we will explicitly compute the attached CM el
liptic curve. An analogue of this association was used by Laga-Shnidman to
get results on vanishing of Ceresa cycles for Picard curves. Based on ong
oing work with Francesc Fite and Pip Goodman.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Youcis (University of Toronto)
DTSTART:20260330T200000Z
DTEND:20260330T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/46
DESCRIPTION:Title: A new approach to canonical integral models of Shimura varieties\
nby Alex Youcis (University of Toronto) as part of Boston University Numbe
r Theory Seminar\n\nLecture held in CDS Room 548 in Boston University.\n\n
Abstract\nSince Langlands's earliest paper on his now famous program\, can
onical integral models of Shimura varieties have occupied a central role i
n modern number theory. In this talk I will discuss how recent advances in
integral $p$-adic Hodge theory allows one to make great progress in under
standing these models: both in constructing new examples of such models\,
and greatly explicating the structure of already-existing models. No prior
knowledge of advanced $p$-adic Hodge theory or Shimura varieties will be
assumed\, but familiarity with elliptic curves/abelian varieties and $p$-d
ivisible groups will be very helpful.\n\nThis talk is based on joint works
: one with Keerthi Madapusi\, and the other with Naoki Imai and Hiroki Kat
o.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashvin Swaminathan (Harvard University)
DTSTART:20260406T200000Z
DTEND:20260406T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/47
DESCRIPTION:by Ashvin Swaminathan (Harvard University) as part of Boston U
niversity Number Theory Seminar\n\nLecture held in CDS Room 548 in Boston
University.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Zureick-Brown (Amherst College)
DTSTART:20260413T200000Z
DTEND:20260413T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/48
DESCRIPTION:Title: Angle ranks of Abelian varieties\nby David Zureick-Brown (Amherst
College) as part of Boston University Number Theory Seminar\n\nLecture he
ld in CDS Room 548 in Boston University.\n\nAbstract\nI will discuss an el
ementary notion -- the rank of the multiplicative group generated by roots
of a polynomial. For Weil polynomials one calls this the angle rank. I'l
l present new results about angle ranks and give some applications to the
Tate conjecture for Abelian varieties over finite fields and to arithmetic
statistics.\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Isabel Vogt (Brown University)
DTSTART:20260427T200000Z
DTEND:20260427T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/49
DESCRIPTION:by Isabel Vogt (Brown University) as part of Boston University
Number Theory Seminar\n\nLecture held in CDS Room 365 in Boston Universit
y.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Holiday: Indigenous People's Day
DTSTART:20251013T200000Z
DTEND:20251013T210000Z
DTSTAMP:20260404T094751Z
UID:NTBU/50
DESCRIPTION:by Holiday: Indigenous People's Day as part of Boston Universi
ty Number Theory Seminar\n\nLecture held in CDS Room 548 in Boston Univers
ity.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/NTBU/50/
END:VEVENT
END:VCALENDAR