Universität Jena, Fakultät für Mathematik & Informatik, Institut für Mathematik, Lehrstuhl Algebra

Oberseminar Algebra/Zahlentheorie


Vortragsankündigungen

Bitte beachten Sie auch die Vorträge im Mathematischen Kolloquium.


WS2019/2020

Mittwoch, den 5. Februar 2020, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Boris Kunyavskii   (Bar-Ilan University, Israel)
"Word equations on groups and Lie algebras"
Dienstag, den 4. Februar 2020, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Ksenija Kitanov   (Universität Jena)
"Higher-order congruence relations on affine moment graphs"
Abstract: With any moment graph one can associate its structure algebra, a certain graded commutative algebra over a polynomial ring. For the case of affine moment graphs, after evaluating one variable of this polynomial ring at 0, quite surprising divisibility relations emerge. These relations can be regarded as a generalization of ordinary moment graph relations that define sections of sheaves on moment graphs, and thus we call them higher-order congruence relations.
Dienstag, den 28. Januar 2020, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Simon King   (Universität Jena)
"Vertices, Sources and the Green Correspondence"
Dienstag, den 21. Januar 2020, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Giovanna Carnovale   (Universita` degli Studi di Padova)
"Jordan classes in Lie algebras and algebraic groups"
Abstract: Reductive algebraic groups and Lie algebras can be stratified by means of irreducible, locally closed, smooth unions of elements that have similar Jordan decomposition, called Jordan classes or decomposition classes. In the Lie algebra context they were introduced by Borho and Kraft to describe sheets for the adjoint action, whereas in the algebraic group context they firstly appeared in the work of Lusztig on the generalised Springer correspondence. After showing difference and similarities between the group and the Lie algebra case, I will show how locally the two stratifications can be related and how to deduce geometric properties of the group stratification from properties of the Lie algebra one. The talk is based on joint work with Filippo Ambrosio and Francesco Esposito.
Dienstag, den 14. Januar 2020, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2 Achtung! Ausfall wegen Erkrankung
Dr. Karin Schaller   (FU Berlin)
"Polyhedral Divisors and Orbit Decompositions of Normal Affine Varieties with Torus Action"
Dienstag, den 7. Januar 2020, in JENA, SR 3517, Ernst-Abbe-Platz 2
Algebra-Seminar Halle-Jena,
Gemeinsames Oberseminar mit dem Mathematischen Institut der Universität Halle-Wittenberg
Einladung/Programm
14:15 Uhr
Andriy Regeta   (Universität Jena)
"On the Lie algebras of vector fields of smooth affine surfaces"
Abstract: In this talk we will study the Lie algebra of volume preserving vector fields on affine plane. We will show that this algebra is simple and study its finite-dimensional subalgebras. At the end we will discuss some interesting subalgebras of the Lie algebras of vector fields on the so-called Danielewski surfaces.
15:45 Uhr
Imke Toborg  (MLU Halle-Wittenberg)
"Isolated elements of order p in finite groups without elementary abelian subgroups of order p3"
Abstract: Let $p$ be an odd prime, and let $G$ be a finite group which does not contain elementary abelian subgroups of order $p^3$. Moreover, let $x \in G$ be an element of order $p$ such that $x^G \cap C_G(x) = \{x\}$.
Then $G = C_G(x) \cdot O_{p'}(G)$, or $F^*(G/O_{p'}(G))$ is simple. In the second case we will investigate the structure of a Sylow $p$-subgroup and determine it precisely in case $p=3$.
16:45 Uhr s.t.
Susanne Danz  (KU Eichstätt)
"On Ext-quivers of weight-2 blocks of symmetric groups"
Abstract: Blocks of symmetric groups of weight 2 over fields of odd characteristic p have been studied a lot. Thanks to work of Scopes, Martin, Richards and others the structure of these blocks is now comparatively well understood.
In 1995 Scopes, for instance, proved that all decomposition numbers of a block of weight 2 are at most 1, and the Ext-space of two simple modules is at most one-dimensional. Her proof (in principle) also provides an algorithm to compute the Ext-quiver of any given weight-2 block. In this talk we shall combine this with results of Richards and Chuang--Tan, in order to explicitly determine the Ext-quivers of all weight-2 blocks whose p-cores are hook partitions. As a consequence, we shall also gain information on possible Morita equivalences between different blocks of weight 2.
This is joint work with Karin Erdmann.
Dienstag, den 17. Dezember 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Johannes Hahn   (Universität Jena)
"G-graduierte Algbren und Clifford-Theorie"
Dienstag, den 10. Dezember 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
André Prater   (Universität Jena)
"On blocks with non-cyclic defect groups"
Dienstag, den 3. Dezember 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Andriy Regeta   (Universität Jena)
"On the structure of the automorphism group of an affine variety"
Dienstag, den 19. November 2019, in HALLE/Saale, SR 3, Georg-Cantor-Haus, Theodor-Lieser-Str. 5
Algebra-Seminar Halle-Jena,
Gemeinsames Oberseminar mit dem Mathematischen Institut der Universität Halle-Wittenberg
Einladung/Programm
Dienstag, den 12. November 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Natalia Iyudu   (MPIM, Bonn)
"Noncommutative Poisson structures, Hochschild type complexes and Groebner bases techniques"
Dienstag, den 5. November 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Susanna Fromm   (Universität Jena)
"Eine Verallgemeinerung der Scopes-Äquivalenz"
Dienstag, den 29. Oktober 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Burkhard Külshammer   (Universität Jena)
"Kerne von Moduln und Blöcken"
Dienstag, den 22. Oktober 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Burkhard Külshammer   (Universität Jena)
"On centers and radicals of group algebras and blocks"
Dienstag, den 15. Oktober 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Denis Morozov   (National University of Kyiv-Mohyla Academy)
"Some properties of finite-state automatons’ centralizers"

SS2019

Dienstag, den 9. Juli 2019, in HALLE/Saale, SR 3, Georg-Cantor-Haus, Theodor-Lieser-Str. 5
Algebra-Seminar Halle-Jena,
Gemeinsames Oberseminar mit dem Mathematischen Institut der Universität Halle-Wittenberg
Einladung/Programm
Dienstag, den 2. Juli 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Sofia Brenner  (Universität Jena)
"On the Malle-Navarro Conjecture for blocks of general linear groups"
Dienstag, den 25. Juni 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Stephanie Reinhardt  (Universität Jena)
"Representation theory of AΓL(1, pn)"
Dienstag, den 11. Juni 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Benjamin Sambale  (Universität Jena)
"Tate's Theorem"
Dienstag, den 4. Juni 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Michael Livesey  (Universität Jena)
"The cup product in low dimension and cohomology of cyclic groups"
Dienstag, den 28. Mai 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Simon King  (Universität Jena)
"The Cup Product"
Dienstag, den 21. Mai 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
André Prater  (Universität Jena)
"Compatibility of Restriction and Corestriction"
Dienstag, den 14. Mai 2019, in JENA, SR 3517, Ernst-Abbe-Platz 2
Algebra-Seminar Halle-Jena,
Gemeinsames Oberseminar mit dem Mathematischen Institut der Universität Halle-Wittenberg
Einladung/Programm
14:00 Uhr s.t.
Patrick Salfeld   (MLU Halle-Wittenberg)
"Finite simple permutation groups acting with fixity 2 and their occurrence as groups of automorphisms of Riemann surfaces"
15:30 Uhr s.t.
Ruwen Hollenbach  (TU Kaiserslautern)
"Basic sets for blocks of finite groups of Lie type"
16:45 Uhr s.t.
Michael Livesey   (Universität Jena)
"Donovan's conjecture and related questions"
Abstract: Donovan's conjecture states that for a fixed p-group P there are only finitely many blocks (up to Morita equivalence) with defect group isomorphic to P. In this talk I will talk about recent progress made on this question (particularly for P abelian) and the related questions of classifying blocks with a given defect group and calculating Picard groups for blocks with a fixed defect group. This is joint work with Charles Eaton and Florian Eisele.
Dienstag, den 7. Mai 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Burkhard Külshammer  (Universität Jena)
"The corestriction in group cohomology"
Dienstag, den 30. April 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Johannes Hahn   (Universität Jena)
"Inflation, Restriction & Corestriction"
Dienstag, den 23. April 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. David J. Green   (Universität Jena)
"The long exact cohomology sequence"
Dienstag, den 16. April 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Dr. Michael Livesey   (Universität Jena)
"The definition of cohomology groups"
Dienstag, den 9. April 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Benjamin Sambale   (z. Zt. Universität Jena)
"Introduction to class field theory"

WS 2018/2019

Dienstag, den 5. Februar 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Burkhard Külshammer   (Universität Jena)
"Fong-Charaktere"
Dienstag, den 29. Januar 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Benjamin Sambale   (z. Zt. Universität Jena)
"Gewichte und nilpotente Untergruppen"

Dienstag, den 22. Januar 2019, in JENA, SR 3517, Ernst-Abbe-Platz 2

Algebra-Seminar Halle-Jena,
Gemeinsames Oberseminar mit dem Mathematischen Institut der Universität Halle-Wittenberg
Einladung/Programm
14:15-15:15 Uhr
Burkhard Külshammer  (Universität Jena)
"Die Loewy-Struktur gewisser Fixpunkt-Algebren, Teil II"
15:45-16:45 Uhr
Andreas Bächle  (Vrije Universiteit Brussel)
"Actions on trees of units in integral group rings" 17:00-18:00 Uhr
Rebecca Waldecker   (MLU Halle-Wittenberg)
"Episode III: Die Rache der Orbitalgraphen"
Dienstag, den 15. Januar 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
PD Dr. Simon King   (Universität Jena)
"Castelnuovo-Mumford-Regularität"
Dienstag, den 8. Januar 2019, 14:15 Uhr, SR 3517, Ernst-Abbe-Platz 2
Prof. Burkhard Külshammer   (Universität Jena)
"Die CPW-Basis"

Bisherige Vorträge

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