BEGIN:VCALENDAR
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PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Bernhard Keller (Université de Paris)
DTSTART:20200925T130000Z
DTEND:20200925T134000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/1
DESCRIPTION:Title: Cartan matrices and Calabi-Yau completions\nby Bernhard Keller
(Université de Paris) as part of Sherbrooke Meeting on Representation Th
eory of Algebras\, Corona Edition (fully online)\n\n\nAbstract\nQuantum Ca
rtan matrices and their inverses are of interest in the representation the
ory of quantum affine algebras. We show how to\ncategorify them for simply
laced Dynkin diagrams using bigraded\nCalabi-Yau completions (aka bigrade
d Ginzburg algebras). In particular\, we will recover a formula due to Her
nandez-Leclerc (2015) and\nFujita (2019) expressing the inverse quantum Ca
rtan matrix in\nterms of the (ordinary) derived category and thus in terms
of the combinatorics of the repetition quiver. We will end by discussing\
nthe problem of obtaining analogous results in the non simply laced case.\
n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre-Guy Plamondon (Université de Versailles Saint-Quentin)
DTSTART:20200925T140000Z
DTEND:20200925T144000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/2
DESCRIPTION:Title: The g-vector fan of tame algebras\nby Pierre-Guy Plamondon (Un
iversité de Versailles Saint-Quentin) as part of Sherbrooke Meeting on Re
presentation Theory of Algebras\, Corona Edition (fully online)\n\n\nAbstr
act\nThe $g$-vector fan of an algebra is a simplicial fan whose rays are t
he $g$-vectors of indecomposable rigid $2$-term complexes of projective mo
dules. It appears naturally in many contexts\, including tau-tilting theor
y\, King's stability conditions and categorification of cluster algebras.\
n\nIn this talk\, we will see that the $g$-vector fan of a tame algebra ha
s particularly nice properties. The talk will be a report on a joint work
with Toshiya Yurikusa\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Poster session (gather.town)
DTSTART:20200925T150000Z
DTEND:20200925T170000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/3
DESCRIPTION:Title: **The following are posters\, presented both friday and saturday**
\nby Poster session (gather.town) as part of Sherbrooke Meeting on Rep
resentation Theory of Algebras\, Corona Edition (fully online)\n\nAbstract
: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tianyuan Xu (University of Colorado Boulder)
DTSTART:20200925T170000Z
DTEND:20200925T174000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/4
DESCRIPTION:Title: On Kazhdan-Lusztig cells of a-value 2\nby Tianyuan Xu (Univers
ity of Colorado Boulder) as part of Sherbrooke Meeting on Representation T
heory of Algebras\, Corona Edition (fully online)\n\n\nAbstract\nLusztig's
a-function on a Coxeter group $W$ is a function that takes\n\n\n\na const
ant nonnegative integer value on each Kazhdan--Lusztig cell of $W$. The\n
function plays a key role in the study of the cells of $W$ and the cell\nr
epresentations of the Hecke algebra of $W$\, but it is also very difficult
to\ncompute. For an element $w \\in W$\, it is known that $a(w)=0$ if and
\nonly if $W$ is the identity and $a(w)=1$ if and only if $w$ has a\nuniqu
e nonempty reduced word\; moreover\, the elements of $a$-values $0$\nand $
1$ each form a single two-sided cell. We report on some extensions of thes
e\nresults about the set $W_2$ of elements with $a$-value $2$. In particul
ar\,\nwe classify Coxeter groups $W$ where $W_2$ is finite\, count $W_2$ a
nd describe\nthe partition of $W_2$ into cells when $W_2$ is finite\, and
discuss a\nconnection between cell representations associated to $W_2$ and
the reflection\nrepresentation of $W$ in types ADE. (Joint work with Rich
ard Green.)\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hugh Thomas (Université du Québec à Montréal)
DTSTART:20200925T180000Z
DTEND:20200925T184000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/5
DESCRIPTION:Title: The fundamental theorem of finite semi-distributive lattices\n
by Hugh Thomas (Université du Québec à Montréal) as part of Sherbrooke
Meeting on Representation Theory of Algebras\, Corona Edition (fully onli
ne)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Martsinkovsky (Northeastern University)
DTSTART:20200925T190000Z
DTEND:20200925T194000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/6
DESCRIPTION:Title: Asymptotic aspects of torsion and cotorsion\nby Alex Martsinko
vsky (Northeastern University) as part of Sherbrooke Meeting on Representa
tion Theory of Algebras\, Corona Edition (fully online)\n\n\nAbstract\nThi
s is joint work with Jeremy Russell. In this expository talk\, \nI will re
call the new concepts of torsion and cotorsion\, as expounded \nin our ear
lier work\, and introduce their asymptotic counterparts. Our \nconstructio
n is applicable to any ring. Using the (co)completeness of \nthe category
of finitely presented functors\, I will give an explicit \ndescription of
the right-derived functors of torsion over Artin algebras.\nAll concepts r
elated to functors will be defined and explained.\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yadira Valdivieso Díaz (University of Leicester)
DTSTART:20200926T130000Z
DTEND:20200926T134000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/7
DESCRIPTION:Title: Derived categories of skew-gentle algebras and orbifolds\nby Y
adira Valdivieso Díaz (University of Leicester) as part of Sherbrooke Mee
ting on Representation Theory of Algebras\, Corona Edition (fully online)\
n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Markus Schmidmeier (Florida Atlantic University)
DTSTART:20200926T140000Z
DTEND:20200926T144000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/8
DESCRIPTION:Title: Tableau invariants and how they position objects in the Auslander
-Reiten quiver\nby Markus Schmidmeier (Florida Atlantic University) as
part of Sherbrooke Meeting on Representation Theory of Algebras\, Corona
Edition (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Poster session (gather.town)
DTSTART:20200926T150000Z
DTEND:20200926T160000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/9
DESCRIPTION:Title: **The same posters as Friday are presented\, click on "Past Talks"
to access Friday's schedule**\nby Poster session (gather.town) as par
t of Sherbrooke Meeting on Representation Theory of Algebras\, Corona Edit
ion (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Calin Chindris (University of Missouri-Columbia)
DTSTART:20200926T170000Z
DTEND:20200926T174000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/10
DESCRIPTION:Title: The membership problem for orbit semigroups of quiver\nby Cal
in Chindris (University of Missouri-Columbia) as part of Sherbrooke Meetin
g on Representation Theory of Algebras\, Corona Edition (fully online)\n\n
Abstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frauke Bleher (University of Iowa)
DTSTART:20200926T180000Z
DTEND:20200926T184000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/11
DESCRIPTION:Title: Automorphism groups of pro-free groups and their representations<
/a>\nby Frauke Bleher (University of Iowa) as part of Sherbrooke Meeting o
n Representation Theory of Algebras\, Corona Edition (fully online)\n\n\nA
bstract\nThis is joint work with Ted Chinburg and Alex Lubotzky. Let $d\\g
e 2$\, let $F_d$ be a free discrete group of rank $d$\, and let $\\hat{F}_
d$ be its profinite completion. Grunewald and Lubotzky developed a method
to construct\, under some technical conditions\, representations of finite
index subgroups of $\\mathrm{Aut}(F_d)$ that have as images certain large
arithmetic groups. In this talk\, I will first show how their method lead
s to a stronger result for $\\mathrm{Aut}(\\hat{F}_d)$. I will then discus
s an application of this result to Galois theory. This uses a result by Be
lyi who showed that there is a natural embedding of the absolute Galois gr
oup $G_{\\mathbb{Q}}$ of $\\overline{\\mathbb{Q}}$ over $\\mathbb{Q}$ into
$\\mathrm{Aut}(\\hat{F}_2)$. In particular\, I will show how the natural
action of certain subgroups of $G_{\\mathbb{Q}}$ on the Tate modules of g
eneralized Jacobians of covers of $\\mathbb{P}^1$ over $\\overline{\\mathb
b{Q}}$ that are unramified outside $\\{0\,1\,\\infty\\}$ can be extended\,
up to a finite index subgroup\, to an action of a finite index subgroup o
f $\\mathrm{Aut}(\\hat{F}_2)$. If time permits\, I will give a criterion f
or this action to define\, up to a finite index subgroup\, a compatible ac
tion on the Tate modules of the usual Jacobians of the covers.\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Khrystyna Serhiyenko (University of Kentucky)
DTSTART:20200926T190000Z
DTEND:20200926T194000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/12
DESCRIPTION:Title: Maximal green sequences for string algebras\nby Khrystyna Ser
hiyenko (University of Kentucky) as part of Sherbrooke Meeting on Represen
tation Theory of Algebras\, Corona Edition (fully online)\n\n\nAbstract\nM
aximal green sequences are certain transformations of quivers that were fi
rst introduced by Keller in the context of cluster algebras. Later they w
ere generalized to the setting of finite dimensional algebras\, where a ma
ximal green sequence is a finite maximal chain in the lattice of torsion c
lasses. More recently\, it was shown that these sequences are in bijectio
n with forward hom-orthogonal sequences of bricks in the module category.
We use the latter approach to study existence and number of maximal gree
n sequences for string algebras. This is joint work with A. Garver.\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ralf Schiffler (University of Connecticut)
DTSTART:20200926T200000Z
DTEND:20200926T204000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/13
DESCRIPTION:Title: A proof of two conjectures on Markov Numbers\nby Ralf Schiffl
er (University of Connecticut) as part of Sherbrooke Meeting on Representa
tion Theory of Algebras\, Corona Edition (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Barnard and Eric Hanson (DePaul University and Brandeis Univ
ersity)
DTSTART:20200925T150000Z
DTEND:20200925T153000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/14
DESCRIPTION:Title: ROOM 1: Pairwise Compatibility for 2-Simple Minded Collections\nby Emily Barnard and Eric Hanson (DePaul University and Brandeis Univer
sity) as part of Sherbrooke Meeting on Representation Theory of Algebras\,
Corona Edition (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Job D. Rock (Hausdorff Research Institute for Mathematics)
DTSTART:20200925T151000Z
DTEND:20200925T154000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/15
DESCRIPTION:Title: ROOM 2: Pointwise Finite-Dimensional Representations of the Circl
e\nby Job D. Rock (Hausdorff Research Institute for Mathematics) as pa
rt of Sherbrooke Meeting on Representation Theory of Algebras\, Corona Edi
tion (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karin Baur (University of Leeds)
DTSTART:20200925T152000Z
DTEND:20200925T155000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/16
DESCRIPTION:Title: ROOM 3: Orbifold diagrams and skew group categories\nby Karin
Baur (University of Leeds) as part of Sherbrooke Meeting on Representatio
n Theory of Algebras\, Corona Edition (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Özgür Esentepe (University of Connecticut)
DTSTART:20200925T153000Z
DTEND:20200925T160000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/17
DESCRIPTION:Title: ROOM 4: Orders over CM local rings with positive CM dominant dime
nsion\nby Özgür Esentepe (University of Connecticut) as part of Sher
brooke Meeting on Representation Theory of Algebras\, Corona Edition (full
y online)\n\n\nAbstract\nI will try to show you that some orders over Cohe
n-Macaulay local rings have derived dimension bounded above by twice the K
rull dimension of the base ring. The main ingredients are a condition on t
he dominant dimension inside the category of centrally Cohen-Macaulay modu
les and a condition on the Nakayama functor again on the same category. Th
e first condition gives rise to a canonical tilting module whose endomorph
ism algebra is nicer if the order we start with has large global dimension
. The second condition guarantees that we can iterate this process.The ide
as from this work are similar to the works of Hongxing Chen-Changchang Xi
and Matthew Pressland-Julia Sauter. However\, they reveal new results when
the base ring is of positive Krull dimension.This work is still ongoing.\
n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maxime Fairon (University of Glasgow)
DTSTART:20200925T154000Z
DTEND:20200925T161000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/18
DESCRIPTION:Title: ROOM 5: Géométrie de Poisson non-commutative et systèmes inté
grables / Noncommutative Poisson geometry and integrable systems\nby
Maxime Fairon (University of Glasgow) as part of Sherbrooke Meeting on Rep
resentation Theory of Algebras\, Corona Edition (fully online)\n\nAbstract
: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edson Ribeiro Alvares (Universidade Federal do Paraná)
DTSTART:20200925T155000Z
DTEND:20200925T162000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/19
DESCRIPTION:Title: ROOM 6: On the braid group action on exceptional sequences for we
ighted projective lines\nby Edson Ribeiro Alvares (Universidade Federa
l do Paraná) as part of Sherbrooke Meeting on Representation Theory of Al
gebras\, Corona Edition (fully online)\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriella D'Este (University of Milano)
DTSTART:20200925T160000Z
DTEND:20200925T163000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/20
DESCRIPTION:Title: ROOM 7: Isomorphisms and extensions of uniserial modules\nby
Gabriella D'Este (University of Milano) as part of Sherbrooke Meeting on R
epresentation Theory of Algebras\, Corona Edition (fully online)\n\n\nAbst
ract\nThe first open problems in Auslander - Reiten - Smalo book " Repr
esentation\nTheory of Artin algebras " deal with uniserial modules. In
particular Problem 1\ndeals with the isomorphism problem for uniserial mod
ules\, while Problem 3\ndeals with the extension problem for the same modu
les.\nI will present a partial solution to Problems 1 and 3 obtained in
two joint\npapers with Fatma Kaynarca and Derya Keskin Tutuncu.\nConcern
ing the isomorphism problem\, we obtain a " two fixed point\ntheorem" .
Finally\, concerning the extension problem we obtain a\n" two terms in the
middle theorem" .\nGoogle and the words " Isomorphism problem for uniseri
al modules over\narbitrary rings " give the file of our first paper in Com
m. Algebra (April 2020).\nGoogle and the words " Forthcoming articles\, M
athematics\, Padova " \ngive the link to our second paper " Extensions o
f uniserial modules " \,\nacceped for publication in Rendiconti del Semina
rio Matematico\ndell'Università di Padova.\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephen Zito (University of Connecticut)
DTSTART:20200925T161000Z
DTEND:20200925T164000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/21
DESCRIPTION:Title: ROOM 8: Tau-Tilting Finite Cluster-Tilted Algebras\nby Stephe
n Zito (University of Connecticut) as part of Sherbrooke Meeting on Repres
entation Theory of Algebras\, Corona Edition (fully online)\n\n\nAbstract\
nLet B be a cluster-tilted algebra. Then B is $\\tau$-tilting finite if a
nd only B is representation-finite.\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shijie Zhu (The University of Iowa)
DTSTART:20200925T162000Z
DTEND:20200925T165000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/22
DESCRIPTION:Title: ROOM 9: Applications of separable extensions of algebras\nby
Shijie Zhu (The University of Iowa) as part of Sherbrooke Meeting on Repre
sentation Theory of Algebras\, Corona Edition (fully online)\n\nAbstract:
TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lunch
DTSTART:20200926T160000Z
DTEND:20200926T170000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/31
DESCRIPTION:Title: on gather.town\nby Lunch as part of Sherbrooke Meeting on Rep
resentation Theory of Algebras\, Corona Edition (fully online)\n\nAbstract
: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:->
DTSTART:20200925T150000Z
DTEND:20200925T150000Z
DTSTAMP:20260404T094150Z
UID:SheRepTh/32
DESCRIPTION:Title: Conference Picture\nby -> as part of Sherbrooke Meeting on Re
presentation Theory of Algebras\, Corona Edition (fully online)\n\nAbstrac
t: TBA\n
LOCATION:https://stable.researchseminars.org/talk/SheRepTh/32/
END:VEVENT
END:VCALENDAR