Demushkin groups of uncountable rank

Seminar
Speaker
Tamar Bar-On (Oxford)
Date
20/09/2023 - 11:30 - 10:00Add to Calendar 2023-09-20 10:00:00 2023-09-20 11:30:00 Demushkin groups of uncountable rank Demushkin groups play an important rule in number theory, being the maximal pro-p Galois groups of local fields. In 1996 Labute presented a generalization of the theory for countably infinite rank pro-p groups, and proved that the p-Sylow subgroups of the absolute Galois groups of local fields are Demushkin groups of infinite countable rank. These results were extended by Minac & Ware, who gave necessary and sufficient conditions for Demushkin groups of infinite countable rank to occur as absolute Galois groups. In a joint work with Prof. Nikolay Nikolov, we extended this theory to Demushkin groups of uncountable rank. Since for uncountable cardinals there are the maximal possible number of nondegenerate bilinear forms, the class of Demushkin groups of uncountable rank is much richer, and in particular, the groups are not determined completely by their invariants, in contrast to the countable case.   We present some results about the structure of Demushkin groups of uncountable rank, as well as equivalent conditions for being a Demushkin group, and investigate their ability to be realized as absolute Galois groups.   ================================================ https://us02web.zoom.us/j/87856132062 Meeting ID: 878 5613 2062 Third floor seminar room and Zoom אוניברסיטת בר-אילן - המחלקה למתמטיקה mathoffice@math.biu.ac.il Asia/Jerusalem public
Place
Third floor seminar room and Zoom
Abstract

Demushkin groups play an important rule in number theory, being the maximal pro-p Galois groups of local fields. In 1996 Labute presented a generalization of the theory for countably infinite rank pro-p groups, and proved that the p-Sylow subgroups of the absolute Galois groups of local fields are Demushkin groups of infinite countable rank. These results were extended by Minac & Ware, who gave necessary and sufficient conditions for Demushkin groups of infinite countable rank to occur as absolute Galois groups.

In a joint work with Prof. Nikolay Nikolov, we extended this theory to Demushkin groups of uncountable rank. Since for uncountable cardinals there are the maximal possible number of nondegenerate bilinear forms, the class of Demushkin groups of uncountable rank is much richer, and in particular, the groups are not determined completely by their invariants, in contrast to the countable case.  

We present some results about the structure of Demushkin groups of uncountable rank, as well as equivalent conditions for being a Demushkin group, and investigate their ability to be realized as absolute Galois groups.  

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https://us02web.zoom.us/j/87856132062

Meeting ID: 878 5613 2062

תאריך עדכון אחרון : 11/09/2023