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Online seminář z algebry - 12.11.2020 |
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Další seminář z algebry se koná 12.11.2020 od 13.00 online na platformě ZOOM. Informace pro připojení a další program semináře je zde. Marcos Mazari-Armida (Carnegie Mellon University)
Model-theoretic stability and superstability in classes of modules
Abstrakt:
Dividing lines in complete first-order theories were introduced by Shelah in the early seventies. A dividing line is a property such that the classes satisfying such a property have some nice behaviour while those not satisfying it have a bad one. Two of the best understood dividing lines are those of stability and superstability.
In this talk, I will study the notion of stability and superstability in abstract elementary classes of modules with respect to pure embeddings, i.e., classes of the form (K,≤p) where K is a class of R-modules for a fixed ring R and ≤p is the pure submodule relation. In particular, using that the class of p-groups with pure embed- dings is a stable AEC, I will present a solution to Problem 5.1 in page 181 of Abelian Groups by Laszlo Fuchs. Moreover, I will show how the notion of superstability can be used to give new characterizations of noetherian rings, pure-semisimple rings, and perfect rings.
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Aktualizováno Úterý, 10 Listopad 2020 15:17 |
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Online seminář z diferenciální geometrie - 9.11.2020 |
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Seminář z diferenciální geometrie pokračuje 9.11.2020 od 10:00 online na platformě MS Teams
Připojení ke schůzce ZDE. Andrei Dikarev (ÚMS):On holonomy of Weyl connections in Lorentzian signature Abstrakt:
I will present my recent results about the classification of the holonomy algebras of Weyl connections in Lorentzian signature. A special attention will be paid to the construction of examples of Weyl connections with different holonomy algebras. |
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Aktualizováno Pátek, 30 Říjen 2020 15:58 |
