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summer 2000
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Wojciech J. Gajda

professor of mathematics

Mailing address:
Faculty of Mathematics and Computer Science
Adam Mickiewicz University
Umultowska 87, 61-614 Poznań, POLAND
Office: Collegium Mathematicum, B1-35
Phone: +48 (61) 829 5503
Fax: +48 (61) 829 5315
Email: gajda AT amu DOT edu DOT pl

Research interests:

arithmetic geometry, number theory, algebraic topology, algebraic K-theory


Damian Rössler, University of Oxford

17.04.2019 11:00, B1-37

Title: Perfect points on curves


We shall describe a proof of the fact that if C is a curve over a global field K of positive characteristic, whose Kodaira-Spencer class is non trivial, then C(K^perf) is finite. We shall also give small upper bounds for #C(K^perf). Here K^perf is the maximal purely inseparable algebraic extension of K. The fact that C(K^perf) is finite is a theorem of Minhyong Kim. His argument uses the theory of heights. By contrast, our argument is purely geometric and it quickly leads to simple estimates of the size of C(K^perf).