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TZID:Asia/Jerusalem
X-WR-TIMEZONE:Asia/Jerusalem
BEGIN:VEVENT
UID:30@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230330T123000
DTEND;TZID=Asia/Jerusalem:20230330T143000
DTSTAMP:20230330T061449Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-poisso
n-lie-groups-and-cluster-structures/
SUMMARY:Cable Car Algebra Seminar: Poisson-Lie groups and cluster structure
s
DESCRIPTION:Lecturer:Alek Vainstein (Haifa U.)\n Location:Amado 814\n It is
well known that cluster structures and Poisson structures in the algebra
of regular functions on a quasi-affine variety are closely related. In thi
s talk\, I will discuss this connection for Poisson structures on a simple
simply connected complex Lie group G defined by a pair of classical R-mat
rices. The key element of the construction is a rational Poisson map from
the group with a bracket defined by pair of suitably chosen standard R-mat
rices to the same group with an arbitrary pair of R-matrices. In the case\
, of G=SL_n one can build explicitly the corresponding cluster structure a
nd prove its regularity and completeness.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:36@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230420T120000
DTEND;TZID=Asia/Jerusalem:20230420T130000
DTSTAMP:20230414T150941Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-semior
thogonal-decompositions-of-derived-categories-of-moduli-spaces-of-vector-b
undles-on-a-curve/
SUMMARY:Cable Car Algebra Seminar: Semiorthogonal decompositions of derived
categories of moduli spaces of vector bundles on a curve.
DESCRIPTION:Lecturer:Jenia Tevelev (U. Mass. Amherst)\n Location:U. Haifa\,
Main building room 626\n Let C be a smooth projective curve of genus at l
east 2 and let N be the moduli space of stable rank 2 vector bundles on C
with fixed odd determinant. We construct a semi-orthogonal decomposition o
f the bounded derived category of N conjectured by Narasimhan and by Belma
ns\, Galkin and Mukhopadhyay. It has two blocks for each i-th symmetric po
wer of C for i = 0\,...\,g−2 and one block for the (g − 1)-st symmetri
c power.\nThe proof contains two parts. Semi-orthogonality\, proved jointl
y with Sebastian Torres\, relies on hard vanishing theorems for vector bun
dles on the moduli space of stable pairs. The second part\, elimination of
the phantom\, requires analysis of weaving patterns in derived categories
.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:37@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230420T130000
DTEND;TZID=Asia/Jerusalem:20230420T140000
DTSTAMP:20230414T151533Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-derang
ements-in-permutation-groups/
SUMMARY:Cable Car Algebra Seminar: Derangements in permutation groups
DESCRIPTION:Lecturer:Danielle Garzoni (Tel Aviv University)\n Location:U. H
aifa\, Main building room 626\n Given a group G acting on a set X\, an ele
ment g of G is called a derangement if it acts without fixed points on X.
The Boston--Shalev conjecture\, proved by Fulman and Guralnick\, asserts t
hat in a finite simple group G acting transitively on X\, the proportion o
f derangements is at least some absolute constant c >\; 0. We will first
give an introduction to the subject\, highlighting some connections with
number theory. Then\, we will see a version of this conjecture for the pro
portion of *conjugacy classes* containing derangements in finite groups of
Lie type. Joint work with Sean Eberhard.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:50@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230511T120000
DTEND;TZID=Asia/Jerusalem:20230511T130000
DTSTAMP:20230425T074919Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-comple
ted-pbw-theorem-and-massey-operations-in-cohomology-of-nilpotent-lie-algeb
ras/
SUMMARY:Cable Car Algebra Seminar: Completed PBW theorem and Massey operati
ons in cohomology of nilpotent Lie algebras
DESCRIPTION:Lecturer:Grigory Papayanov (North Eastern University &\; Wei
zmann Institute)\n Location:U. Haifa\, Main building room 626\n The usual
PBW theorem states that for a Lie algebra $g$ over a field of characterist
ic zero the associated graded algebra of the universal enveloping $Ug$ wit
h respect to the degree filtration is isomorphic to the symmetric algebra
of $g$. The completed PBW theorem concerns the structure of the completion
of $Ug$ in the augmentation ideal. The simplest examples shows that the c
ompleted PBW theorem does not hold for general Lie algebras. We'll show th
at it\, nevertheless\, holds for nilpotent Lie algebras. As a consequence\
, we'll prove that the cohomology algebra $H(g)$ of a nilpotent Lie algebr
a is generated by $H^1(g)$ by (suitably defined) Massey operations. We'll
also discuss why the more natural setting for this problem is that of coal
gebras instead of algebras and some consequences of computations of cohomo
logy of nilpotent Lie algebras.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:51@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230511T130000
DTEND;TZID=Asia/Jerusalem:20230511T140000
DTSTAMP:20230425T080519Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-genera
lized-geometry-through-clifford-algebra-glasses/
SUMMARY:Cable Car Algebra Seminar: Generalized geometry through Clifford al
gebra glasses
DESCRIPTION:Lecturer:Roberto Rubio (Universitat Autònoma de Barcelona)\n
Location:U. Haifa\, Main building room 626\n Generalized geometry is a rec
ent approach to geometric structures encompassing symplectic and complex g
eometry. At its heart lies a Clifford module\, which is essentially a glob
al version of the spin representation of the Clifford algebra.\nIn this ta
lk I will give an introduction to generalized geometry from the Clifford a
lgebra viewpoint\, survey the main achievements of the theory and mention
some recent results (joint with Joan Porti) concerning 3-manifolds.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:52@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230521T123000
DTEND;TZID=Asia/Jerusalem:20230521T133000
DTSTAMP:20230425T080932Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-on-tem
pered-representations/
SUMMARY:Cable Car Algebra Seminar: On tempered representations
DESCRIPTION:Lecturer:Alexander Yom Din (Hebrew University)\n Location:Techn
ion\, Amado Building 814\n Given a locally compact group G\, the decomposi
tion of the space of square integrable functions on G into irreducible uni
tary representations of G (“irreps”) is one of the basic desires in ha
rmonic analysis. Not all irreps appear in such a decomposition\; those whi
ch do are called tempered. The decomposition has a discrete as well as a c
ontinuous parts\; the irreps which appear in the discrete part are called
square integrable\, and are much simpler analytically than general tempere
d irreps. Loosely speaking\, tempered irreps can be thought of as “on th
e verge” of being square integrable. Although this intuition is rather c
lassical\, we discuss a new possible formal interpretation of it. This is
joint work with D. Kazhdan.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:83@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230601T133000
DTEND;TZID=Asia/Jerusalem:20230601T143000
DTSTAMP:20230531T061234Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-the-wa
vefront-set-of-unipotent-representations-with-real-infinitesimal-character
/
SUMMARY:Cable Car Algebra Seminar: The wavefront set of unipotent represent
ations with real infinitesimal character
DESCRIPTION:Lecturer:Emile Okada (National University of Singapore)\n Locat
ion:Technion\, Amado Building 814\n For a reductive group defined over a p
-adic field\, the wavefront set is an invariant of an admissible represent
ations which roughly speaking measures the direction of the singularities
of the character near the identity. Studied first by Roger Howe in the 70s
\, the wavefront set has important connections to Arthur packets\, and has
been the subject of thorough investigation in the intervening years. One
of main open lines of inquiry is to determine the relation between the wav
efront set and the L-parameter of a representation. In this talk I will pr
esent new results answering this question for unipotent representation wit
h real infinitesimal character. The results are joint with Dan Ciubotaru a
nd Lucas Mason-Brown.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:85@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230608T120000
DTEND;TZID=Asia/Jerusalem:20230608T130000
DTSTAMP:20230601T150533Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-a-vari
ant-of-harish-chandra-functors/
SUMMARY:Cable Car Algebra Seminar: A variant of Harish-Chandra functors
DESCRIPTION:Lecturer:Uri Onn (Australian National University)\n Location:U.
of Haifa\, Main Building\, Auditorium 626\n Harish-Chandra induction and
restriction functors play a key role in the\nrepresentation theory of redu
ctive groups over finite and local fields.\nConstraining a trivial action
by appropriate unipotent subgroups\, which is part of their definition\, r
esults in simple combinatorial commutation relation between induction and
restriction from and to Levi subgroups. This allows one to effectively con
struct and classify representations of such groups. In this talk I will de
scribe generalisations of these functors that are suitable for profinite g
roups.\nThis is a joint work with Tyrone Crisp and Ehud Meir.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:86@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230608T130000
DTEND;TZID=Asia/Jerusalem:20230608T140000
DTSTAMP:20230601T150738Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-functo
r-morphing-in-representation-theory/
SUMMARY:Cable Car Algebra Seminar: Functor morphing in representation theor
y
DESCRIPTION:Lecturer:Ehud Meir (University of Aberdeen)\n Location:U. of Ha
ifa\, Main Building\, Auditorium 626\n A large part of classical represent
ation theory is about reducing the study of irreducible representation of
groups to combinatorial families.\nIn many cases\, this is being done indu
ctively\, using methods such as Clifford Theory and the well known represe
ntation theory of Heisenberg groups.\nIn this talk I will describe a new m
ethod\, called functor morphing\, for reduction of representations of auto
morphism groups of finite modules over finite rings\, by using new methods
developed in symmetric monoidal categories\, that in turn relate to geome
tric invariant theory.\nThis is a joint work with Tyrone Crisp and Uri Onn
\, and a continutation of the first talk of the seminar.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:100@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230615T120000
DTEND;TZID=Asia/Jerusalem:20230615T130000
DTSTAMP:20230614T064139Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-root-g
roupoid-and-lie-superalgebras/
SUMMARY:Cable Car Algebra Seminar: Root groupoid and Lie superalgebras
DESCRIPTION:Lecturer:Vladimir Hinich (University of Haifa)\n Location:U. of
Haifa\, Main Building\, Auditorium 626\n We introduce a notion of a root
groupoid as a replacement of the notion of Weyl group for (Kac-Moody) Lie
superalgebras. The objects of the root groupoid classify certain root data
\, the arrows are defined by generators and relations. As an abstract grou
poid the root groupoid has many connected components and we show that to s
ome of them one can associate an interesting family of Lie superalgebras w
hich we call root superalgebras.\nTo each root groupoid component we assoc
iate a graph (called skeleton) generalizing the Cayley graph of the Weyl g
roup. The skeleton satisfies a version of Coxeter property generalizing th
e fact that the Weyl group of a Kac-Moody Lie algebra is Coxeter.\nThis ta
lk in based on a joint work with V. Serganova and M. Gorelik\, arXiv:2209.
06253.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:101@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230615T130000
DTEND;TZID=Asia/Jerusalem:20230615T140000
DTSTAMP:20230614T064407Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-tropic
al-methods-in-a1-enumerative-geometry/
SUMMARY:Cable Car Algebra Seminar: Tropical Methods in $A^1$-Enumerative Ge
ometry
DESCRIPTION:Lecturer:Andrés Jaramillo Puentes (Universität Duisburg-Essen
)\n Location:U. of Haifa\, Main Building\, Auditorium 626\n Motivic homoto
py theory allows us to tie together the results from classical and real en
umerative geometry\, and yield invariant counts of solutions to geometric
questions over an arbitrary field k. The enumerative counts are valued in
the Grothendieck-Witt ring GW(k) of non- degenerate quadratic forms over k
and we call it quadratic enrichment.\nIn this talk\, I will detail some e
xamples of these counts and I will present a quadratically enriched versio
n of the Bernstein–Khovanskii–Kushnirenko theorem\, as well as a quadr
atically enriched version of the Correspondence Theorem for counting curve
s passing through configurations of k- rational points.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:104@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230622T123000
DTEND;TZID=Asia/Jerusalem:20230622T133000
DTSTAMP:20230621T094430Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-on-the
-hilbert-property-in-several-variables/
SUMMARY:Cable Car Algebra Seminar: On the Hilbert Property in Several Varia
bles
DESCRIPTION:Lecturer:Pierre Debes (Lille University)\n Location:Technion\,
Amado Building\, Room 814\n Given an algebraic situation described by $n\\
geq 1$ variables and depending on $r\\geq 1$ independent parameters\, the
Hilbert property makes it possible to specialize the parameters and preser
ve the structure of the situation. The classical application\, in the situ
ation of $n=1$ variable reduces the Inverse Galois Problem to the search o
f geometric Galois covers of the line defined over the rationals. The main
part of the talk will be devoted to the less classical situation of sever
al variables ($n>\;1$). We will explain how it has led to recent progres
s in several topics: arithmetic Bertini theorems\, polynomial versions of
the Schinzel Hypothesis\, the dimension growth conjecture\, etc.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:126@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20231116T123000
DTEND;TZID=Asia/Jerusalem:20231116T133000
DTSTAMP:20231113T122721Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-bi-int
erpretations-and-their-application-to-chevalley-groups/
SUMMARY:Cable Car Algebra Seminar: Bi-interpretations and their application
to Chevalley groups
DESCRIPTION:Lecturer:Helen Bunina (Bar Ilan)\n Location:Technion\, Amado Bu
ilding\, Room 814\n We will introduce different types of bi-interpretation
s and show how to apply them to algebraic and model-theoretic problems of
Chevalley groups over fields.\nFor example:\n1. We will show that any grou
p elementary equivalent to some Chevalley group is a Chevalley group itsel
f.\n2. We will show that the Diophantine problem in any Chevalley group ov
er a ring R is equivalent to the Diophantine problem of R.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:127@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20231116T134000
DTEND;TZID=Asia/Jerusalem:20231116T144000
DTSTAMP:20231113T122922Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-the-to
pology-and-arithmetic-of-hurwitz-spaces-lecture-1/
SUMMARY:Cable Car Algebra Seminar: The Topology and Arithmetic of Hurwitz S
paces (lecture 1)
DESCRIPTION:Lecturer:Mark Shusterman (Weizmann)\n Location:Technion\, Amado
Building\, Room 814\n Hurwitz spaces are certain (finite) covers of confi
guration spaces of points on a line associated to a (finite) group G.\nIn
topology\, one is interested in the monodromy (group) of these covers\, an
d in computing the homology of Hurwitz spaces. Such problems can also be s
tated in terms of the fundamental groups of these configuration space - th
e braid groups.\nIn geometry\, one views Hurwitz spaces as moduli spaces o
f ramified G-covers of a line. An understanding of the set of such covers
defined over global fields\, or over finite fields\, has implications to t
he qualitative and quantitative inverse Galois problem. It turns out that
topological information about Hurwitz spaces helps make progress toward su
ch arithmetic problems.\nWe will survey this landscape emphasizing the mor
e elementary open problems and approaches.\n(This is the first lecture fro
m two talks\, the second one will be next week November 23.)\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:138@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20231207T123000
DTEND;TZID=Asia/Jerusalem:20231207T133000
DTSTAMP:20231204T075438Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-arithm
etic-local-systems-and-siegel-linearization/
SUMMARY:Cable Car Algebra Seminar: Arithmetic Local Systems and Siegel Line
arization
DESCRIPTION:Lecturer:Borys Kadets (Hebrew University) \n Location:Technion\
, Amado Building\, Room 814\n In a joint work with Daniel Litt we borrow i
deas from complex dynamics to show that for any normal variety X/k there i
s an integer N\, such that any l-adic arithmetic local system on X which i
s trivial modulo l^N is trivial. In this talk I will explain the meaning o
f all of the words in the previous sentence\, how this result relates to c
oncrete questions in arithmetic\, and what all of this has to do with Sieg
el disks inside noncommutative balls.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:139@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20231207T134000
DTEND;TZID=Asia/Jerusalem:20231207T144000
DTSTAMP:20231204T075633Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-combin
atorial-wall-crossing-via-the-mullineux-involution/
SUMMARY:Cable Car Algebra Seminar: Combinatorial wall-crossing via the Mull
ineux involution
DESCRIPTION:Lecturer:Galyna Dobrovolska (Ariel University)\n Location:Techn
ion\, Amado Building\, Room 814\n The rational Cherednik algebra H_c is an
algebra of interest in modern representation theory\, which is a degenera
tion of the double affine Hecke algebra\, introduced by Cherednik to prove
Macdonald's conjectures about properties of Macdonald polynomials. For va
lues of c lying in chambers separated by walls\, representations of H_c ar
e labeled by partitions. Combinatorial wall-crossing is a bijection from t
he set of irreducible representations of H_c to the set of irreducible rep
resentations of H_c'\, where c and c' lie in adjacent chambers separated b
y a wall. Combinatorial wall-crossing across one wall was proven by Losev
to be equal in large positive characteristic to an extension of the Mullin
eux involution from the modular representation theory of the symmetric gro
up. We will exhibit interesting patterns in combinatorial wall-crossing\,
both proven and observed in computer experiments and use them to prove and
refine parts of the conjecture of Bezrukavnikov.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:145@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240111T123000
DTEND;TZID=Asia/Jerusalem:20240111T133000
DTSTAMP:20240104T175407Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-probab
ilistic-galois-theory-in-function-fields/
SUMMARY:Cable Car Algebra Seminar: Probabilistic Galois theory in function
fields
DESCRIPTION:Lecturer:Alexei Entin (Tel Aviv University)\n Location:Technion
\, Amado Building\, Room 814\n Probabilistic Galois Theory studies the dis
tribution of Galois groups in various natural ensembles of Galois extensio
ns of global fields.\nThis area goes back to the classical result of van d
er Waerden that most polynomials\n$X^n+a_{n-1}X^{n-1}+...+a_0$\, $a_i$ int
egers\, $|a_i|<\;H$\nhave Galois group $S_n$ over $Q$ (n fixed\, $H \\to
infty$) and has seen much activity and progress in recent years.\n\nIn th
e talk I will survey the history of Probabilistic Galois Theory and recent
developments in the area and discuss recent work joint with Alexander Pop
ov\, Lior Bary-Soroker and Eilidh McKemmie on the distribution of Galois g
roups over $F_q(t)$ (where $q$ is a prime power) of polynomials of the for
m\n$X^n+a_{n-1}(t)X^{n-1}+...+a_0(t)$\, $a_i(t) \\in F_q[t]$ as well as ad
ditive polynomials of the form $X^{q^n}+a_{n-1}(t)X^{q^{n-1}}+...+a_0(t)X\
,$ $a_i(t) \\in F_q[t].$\n\nA novel feature of the latter family is that i
t involves polynomials with Galois group $GL_n(q)$ and variants\, while pr
eviously studied families involved variants of $S_n$. The main results rel
y crucially on deep results on subgroups of $GL_n(q)$\, combined with a va
riety of tools from algebra and analytic number theory.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:146@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240111T134000
DTEND;TZID=Asia/Jerusalem:20240111T144000
DTSTAMP:20240104T175539Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-distin
ction-of-the-steinberg-representation-with-respect-to-a-symmetric-pair/
SUMMARY:Cable Car Algebra Seminar: Distinction of the Steinberg representat
ion with respect to a symmetric pair
DESCRIPTION:Lecturer:Jiandi Zou (Technion)\n Location:Technion\, Amado Buil
ding\, Room 814\n Let $G$ be a reductive group over a non-archimedean loca
l field $F$ of residual characteristic $p\neq 2$\, let $\\theta$ be an inv
olution of $G$ over $F$ and let $H$ be the connected component of the $\\t
heta$-fixed subgroup of $G$. We are interested in the problem of distincti
on of the Steinberg representation $St_{G}$ of $G$ restricted to $H$. More
precisely\, first we give a reasonable upper bound of the dimension of th
e complex vector space\n$$Hom_H(St_G|_H\,C)$$\nwhich was previously known
to be finite\, and secondly we calculate this dimension for special symmet
ric pairs $(G\,H)$. For instance\, the most interesting case for us is whe
n $G$ is a general linear group and $H$ is an orthogonal subgroup of $G$.\
n\nOur method follows from the previous results of Broussous--Court\\`es o
n Prasad's conjecture. The basic idea is to realize $St_{G}$ as the $G$-sp
ace of complex harmonic cochains on the Bruhat--Tits building of $G$. Thus
the problem is somehow reduced to the combinatorial geometry of the Bruha
t--Tits building. This is a joint work with Chuijia Wang.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:164@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240208T123000
DTEND;TZID=Asia/Jerusalem:20240208T133000
DTSTAMP:20240201T081310Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-height
-bounds-galois-orbits-and-unlikelty-intersections/
SUMMARY:Cable Car Algebra Seminar: Height bounds\, Galois orbits\, and Unli
kely Intersections
DESCRIPTION:Lecturer:Georgios Papas (HUJI) \n Location:Technion\, Amado Bui
lding\, Room 814\n The Zilber-Pink conjecture is a far reaching and widely
open conjecture in the area of unlikely intersections generalizing many p
revious results in the area such as the André-Oort conjecture. Through va
riations of a strategy first introduced by Pila and Zannier\, one can redu
ce this conjecture for curves in certain Shimura varieties to upper bounds
for the size of Galois orbits of so called "atypical points" on such curv
es. We discuss how recent advances in a method first introduced by Y. Andr
é that produces height bounds help us establish these upper bounds for Ga
lois orbits\, and thus cases of Zilber-Pink\, for certain curves in spaces
such as $Y(1)^n$ and $\\mathcal{M}_g$.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:165@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240208T134000
DTEND;TZID=Asia/Jerusalem:20240208T144000
DTSTAMP:20240201T081514Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-specia
lization-of-galois-groups-and-related-low-genus-phenomena/
SUMMARY:Cable Car Algebra Seminar: Specialization of Galois groups and rela
ted low-genus phenomena
DESCRIPTION:Lecturer:Tali Monderer (Technion)\n Location:Technion\, Amado B
uilding\, Room 814\n Given an irreducible bivariate polynomial f(t\,x) w
ith rational coefficients\, what groups H appear as the Galois group of f(
t'\,x) for infinitely many rationals t'? A key step in the investigation o
f this question\, and many others relating to specialization and reducibil
ity\, lies in determining the subcoverings of genus 0 and 1 of the corresp
onding Galois cover of the projective line. We determine\, for several fam
ilies of Galois covers of large degree\, the low genus subcovers\; and des
cribe applications to the specialization problem described above and to th
e Davenport-Lewis-Schinzel problem regarding reducibility of curves given
by the equation h(x)=g(y).\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:189@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240215T143000
DTEND;TZID=Asia/Jerusalem:20240215T153000
DTSTAMP:20240214T090757Z
URL:https://math.technion.ac.il/en/events/projective-bridgeland-semistable
-moduli-spaces-on-quotient-stacks/
SUMMARY:Projective Bridgeland Semistable Moduli Spaces on Quotient Stacks
DESCRIPTION:Lecturer:Tal Ben-Yehuda (Technion)\n Location:Amado 814\n Modul
i spaces are fundamental objects of interest across mathematics and physic
s. These spaces parametrize isomorphism classes of algebro-geometric objec
ts\, which come about frequently as solutions to classification problems.
In algebraic geometry\, of special interest are moduli spaces of coherent
sheaves on smooth projective varieties. A fruitful approach to studying th
ese moduli spaces is via Fourier-Mukai transforms on the bounded derived c
ategory D^b(CohX)\, built as the category of complexes of coherent sheaves
on X\, up to quasi-isomorphism. But these autoequivalences do not always
take sheaves to sheaves. Enter Bridgeland's stability conditions - these
conditions\, whose origins began in string theory\, allow us to apply aut
oequivalences freely and use our intuition from classical stability. Under
suitable assumptions\, for each stability condition and each numerical cl
ass\, moduli spaces of stable objects in D^b(X) for an algebraic variety X
\, exist as proper algebraic spaces. This formalism includes many previous
ly studied moduli spaces such as moduli spaces of Giesker or slope-stable
sheaves. For most applications of Bridgeland stability\, one needs proj
ective coarse moduli spaces of Bridgeland semistable objects. One problema
tic aspect of Bridgeland stability is showing that the proper algebraic sp
aces above are in fact projective varieties. Many varieties come about as
quotients of covering varieties by the action of some group G. We prove th
e following conjecture - Let X be a smooth projective variety\, and G a fi
nite cyclic group acting on X. Assume X carries projective Bridgeland semi
stable moduli spaces\, meaning for numerical class v and \\sigma \\in Stab
(X) (a stability condition) the set M_\\sigma(v) of \\sigma-semistable obj
ects of type v is such a projective moduli space\, then the quotient stack
[X/G] has projective Bridgeland semistable moduli spaces as well. This is
helpful to show projectivity in a range of cases\, as well as making a st
ep towards finding a general construction of such moduli spaces.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:166@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240307T123000
DTEND;TZID=Asia/Jerusalem:20240307T133000
DTSTAMP:20240201T081758Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-a-cheb
otarev-density-theorem-over-p-adic-fields/
SUMMARY:Cable Car Algebra Seminar: A Chebotarev density theorem over p-adic
fields.
DESCRIPTION:Lecturer:Asvin G (HUJI) \n Location:Technion\, Amado Building\
, Room 814\n This is joint work with Yifan Wei and John Yin. Recently\, Cr
emona\, Bhargava\, Fisher and Gajovic conjectured that certain naturally o
ccurring factorization densities over the p-adics should form a rational f
unction in the prime p and have a functional equation. Inspired by this co
njecture\, we develop a framework for a p-adic analogue of the Chebotarev
density theorem and prove it assuming the existence of nice resolutions. A
s a consequence of this general framework\, we prove the above conjecture
on factorization densities completely by constructing a nice resolution of
the "resultant locus".\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:202@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240307T134000
DTEND;TZID=Asia/Jerusalem:20240307T144000
DTSTAMP:20240304T105209Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-width-
of-words-in-linear-groups/
SUMMARY:Cable Car Algebra Seminar: Width of words in linear groups.
DESCRIPTION:Lecturer:Pavel Gvozdevsky (Bar Ilan)\n Location:Technion\, Amad
o Building\, Room 814\n A word is an element in a free group. Given a word
$w = w(x_1\, \\dots\, w_k) \\in F_d$ and a group G\, we have the word map
$w: G^k \\to G$ defined by substitution. The set of values w(G) consists
of the image of this map and the inverses of elements of the image. The wi
dth of the word w in the group G is the minimal constant C such that every
element of <\;w(G)>\; can be expressed as the product of C elements o
f w(G).\n\nThe talk will be devoted to known results about width of words
in certain linear groups\, such as algebraic groups over an algebraically
closed field\, compact Lie groups\, finite simple groups\, general linear
groups over a skew field\, and Chevalley groups over commutative rings. Th
e following recent result by the speaker will be discussed in detail:\n\nL
et \\Phi be an irreducible root system of rank at least 2. For every posit
ive integer d there exists a constant $C(\\Phi\, d)$ such that for every r
ing R which is a localization of the ring of integers of a number field of
degree d (with certain additional assumption for the root systems C_2 and
G_2) the width of any word in the simply connected Chevalley group $G(\\P
hi\,R)$ is at most $C(\\Phi\,d)$.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:245@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240606T123000
DTEND;TZID=Asia/Jerusalem:20240606T133000
DTSTAMP:20240529T112917Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-equidi
stribution-of-cm-points/
SUMMARY:Cable Car Algebra Seminar: Equidistribution of CM points
DESCRIPTION:Lecturer:Francesco Maria Saettone (BGU)\n Location:Technion\, A
mado Building\, Room 814\n Equidistribution of "special" points is a theme
of both analytic and geometric interest in number theory: in this talk I
plan to deal with the case of CM points on Shimura curves. The first part
will be devoted to a geometric description of the aforementioned curves an
d of their moduli interpretation. Subsequently\, I plan to sketch an equid
istribution result of reduction of CM points in the special fiber of a Shi
mura curve associated to a ramified quaternion algebra. Time permitting\,
I will mention how Ratner's theorem and subconvexity bounds on Fourier coe
fficients of certain theta series can be used to obtain two different equi
distribution results.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:246@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240606T134000
DTEND;TZID=Asia/Jerusalem:20240606T144000
DTSTAMP:20240529T114621Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-genera
lized-kummer-surfaces-over-finite-fields/
SUMMARY:Cable Car Algebra Seminar: Generalized Kummer surfaces over finite
fields.
DESCRIPTION:Lecturer:Sergey Rybakov (IITP)\n Location:Technion\, Amado Buil
ding\, Room 814\n We classify finite groups that act on abelian surfaces
over a given finite field such that the quotient is birationally equivale
nt to a K3 surface. This is a refinement of the classical result due to Ka
tsura. As a application we study traces of Frobenius for suprsingular K3 s
urfaces over finite fields.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:261@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240627T123000
DTEND;TZID=Asia/Jerusalem:20240627T133000
DTSTAMP:20240616T142211Z
URL:https://math.technion.ac.il/en/events/determining-the-nef-cone-of-the-
hilbert-scheme-of-n-points-on-a-bielliptic-surface-via-bridgeland-stabilit
y/
SUMMARY:Determining the nef cone of the Hilbert scheme of n points on a bie
lliptic surface via Bridgeland stability
DESCRIPTION:Lecturer: Elizaveta Nesterova\n Location:Amado 814\n \nSince Br
idgeland introduced his definition of stability conditions in 2002\, they
have been used to solve various problems in algebraic geometry. Any Brid
geland stability condition gives us a moduli problem and associates to any
Chern character a moduli space\, which for surfaces is known to be an alg
ebraic space. For the Chern character of a Gieseker semi stable sheaf on
a surface\, some special Bridgeland stability conditions (those in the so
-called Gieseker chamber) give back the classical moduli space of semistab
le coherent sheaves constructed by Gieseker and Maruyama. Varying the st
ability conditions allows us to study the relationships between various mo
duli spaces of Bridgeland semi stable objects on surfaces. For example\,
one often obtains birational maps between moduli spaces using wall-crossi
ng methods in the space of Bridgeland stability conditions\, in particular
the natural nef divisor on the moduli space define by. A. Bayer and E. Ma
crì. Thus far\, these techniques have not been used to study moduli space
s associated to bielliptic surfaces. In this talk\, we discuss how using w
all-crossing techniques along with some other insights allows us to determ
ine the nef cone of the moduli space of stable sheaves of Chern class (1\,
0\, -n)\, which corresponds to the Hilbert scheme of n points. Moreover
\, we determine the birational surgery that gives the first minimal model
beyond the boundary of the nef cone. \n\n\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:271@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240704T123000
DTEND;TZID=Asia/Jerusalem:20240704T133000
DTSTAMP:20240630T134519Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-dimer-
models-on-non-orientable-surfaces/
SUMMARY:Cable Car Algebra Seminar: Dimer models on non-orientable surfaces
DESCRIPTION:Lecturer:Sefi Ladkani (UHaifa)\n Location:Technion\, Amado Buil
ding\, Room 814\n A classical dimer model consists of a bipartite graph dr
awn on an orientable closed surface. A dimer model gives rise to a non-com
mutative algebra constructed as a Jacobian algebra of a quiver with potent
ial built from the graph. Various properties of this algebra are reflected
in certain conditions on the dimer model.\nWe propose to extend the notio
n of a dimer model to arbitrary graphs (not necessarily bipartite) drawn o
n arbitrary closed surfaces (which are not necessarily orientable). One mu
st impose some restrictions on the graph in order to be able to construct
a quiver with potential\; it turns out that these restrictions can be expr
essed in terms of bipartiteness of a certain auxiliary graph.\nOur extende
d framework contains all the classical dimer models\, but also gives rise
to new ones consisting of certain graphs on non-orientable surfaces. Some
of these new models have the interesting feature that the finite-dimension
ality of the associated non-commutative algebra depends on the characteris
tic of the ground field.\nAs an application we address the problem of cons
truction and classification of non-degenerate potentials on the exceptiona
l quiver X7 using a dimer model on the real projective plane.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:272@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240704T134000
DTEND;TZID=Asia/Jerusalem:20240704T144000
DTSTAMP:20240630T134657Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-growth
-rate-of-monomial-algebras-and-entropy-in-derived-categories/
SUMMARY:Cable Car Algebra Seminar: Growth rate of monomial algebras and ent
ropy in derived categories
DESCRIPTION:Lecturer:Dmitri Piontkovski (HSE Moscow)\n Location:Technion\,
Amado Building\, Room 814\n Based on the ideas of noncommutative geometry\
, we think about a graded associative algebra as a coordinate ring of a ``
noncommutative projective variety''. The role of the category of coherent
sheaves is\nplayed by the quotient of the category of graded finitely pres
ented A-modules by the finite-dimensional ones. We demonstrate how to reco
ver information about the algebra from its bounded derived category in the
case of monomial and path algebras. In particular\, we calculate the entr
opy in graphs\, algebras\, and derived categories.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:281@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240718T123000
DTEND;TZID=Asia/Jerusalem:20240718T133000
DTSTAMP:20240711T114941Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar/
SUMMARY:Cable Car Algebra Seminar: Symplectic duality and Hikita-Nakajima c
onjecture
DESCRIPTION:Lecturer:Vasily Krylov (MIT)\n Location:Technion\, Amado Buildi
ng\, Room 814\n We will discuss the general notion of symplectic duality (
also known as 3D mirror symmetry) between symplectic resolutions of singul
arities and give examples. We will then formulate the Hikita-Nakajima conj
ecture describing (equivariant) cohomology ring of a symplectic resolution
in terms of the dual variety. We will consider the example of the Hilbert
scheme of points on the affine plane and discuss the proof of the Hikita-
Nakajima conjecture in this particular case. Time permitting\, we will dis
cuss the general approach towards the proof of Hikita-Nakajima conjecture
for other symplectically dual pairs (such as Higgs and Coulomb branches of
certain quiver gauge theories). Various interesting objects (for example\
, integrable systems on Coulomb branches) appear naturally in the proof. B
ased on a joint work with Pavel Shlykov.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:280@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240718T134500
DTEND;TZID=Asia/Jerusalem:20240718T144500
DTSTAMP:20240711T114449Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-homolo
gical-connections-between-glnqp-and-slnc/
SUMMARY:Cable Car Algebra Seminar: Homological connections between GLn(Qp)
and sln(C)
DESCRIPTION:Lecturer:Rida Saabna (Technion)\n Location:Technion\, Amado Bui
lding\, Room 814\n We will discuss the connections between the homological
properties of the representation theory of the general linear group over
a p-adic field and the representation theory of the complex semisimple Lie
algebra sln(C). We use the Arakawa-Suzuki functors\, a family of exact fu
nctors from the BGG category O of sln(C) to the category of finite dimensi
onal modules over the degenerate affine Hecke algebra\, to extract new hom
ological results in the setting of the general linear group from known res
ults in the theory of the category O.\n
CATEGORIES:Algebra Seminar
END:VEVENT
BEGIN:VEVENT
UID:285@math.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20240718T142000
DTEND;TZID=Asia/Jerusalem:20240718T145000
DTSTAMP:20240711T115209Z
URL:https://math.technion.ac.il/en/events/cable-car-algebra-seminar-highes
t-weight-category-for-representations-of-borel-subalgebras/
SUMMARY:Cable Car Algebra Seminar: Highest weight category for representati
ons of Borel subalgebras
DESCRIPTION:Lecturer:Lila Nechaev (Technion)\n Location:Technion\, Amado Bu
ilding\, Room 814\n Highest weight categories are useful for studying the
derived category of a nonsemisimple abelian category. They were introduced
after developments for the BGG category O and modular representations of
symmetric groups. I will recall and advertise this notion and show that ce
rtain natural representations of Borel subalgebras for classical Lie algeb
ras and the Lie superalgebra osp(1|2n) admit a highest weight structure.\n
CATEGORIES:Algebra Seminar
END:VEVENT
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DTSTART:20230324T030000
TZOFFSETFROM:+0200
TZOFFSETTO:+0300
TZNAME:IDT
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BEGIN:STANDARD
DTSTART:20231029T010000
TZOFFSETFROM:+0300
TZOFFSETTO:+0200
TZNAME:IST
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:20240329T030000
TZOFFSETFROM:+0200
TZOFFSETTO:+0300
TZNAME:IDT
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