scholarly journals Geometric criteria for tame ramification

2012 ◽  
Vol 273 (3-4) ◽  
pp. 839-868 ◽  
Author(s):  
Johannes Nicaise
Keyword(s):  
Tame Ramification

An Elementary Proof of a Fixed Point Theorem of J. Lewittes and D. L. McQuillan

1978 ◽  
Vol 21 (1) ◽  
pp. 99-101 ◽  
Author(s):  
Arthur K. Wayman
Keyword(s):  
Fixed Point ◽  
Riemann Surface ◽  
Fixed Point Theorem ◽  
Compact Riemann Surface ◽  
Elementary Proof ◽  
Algebraic Function ◽  
Weierstrass Points ◽  
Algebraic Function Fields ◽  
Genus Formula ◽  
Tame Ramification

In (3), J. Lewittes establishes a connection between the number of fixed points of an automorphism of a compact Riemann surface and Weierstrass points on the surface; Lewittes′ techniques are analytic in nature. In (4), D. L. McQuillan proved the result by purely algebraic methods and extended it to arbitrary algebraic function fields in one variable over algebraically closed ground fields, but with restriction to tamely ramified places. In this paper we will give a different proof of the theorem and show that it is an elementary consequence of the Riemann-Hurwitz relative genus formula. Moreover, we can remove the tame ramification restriction.

scholarly journals Towards an understanding of ramified extensions of structured ring spectra

2018 ◽  
Vol 168 (3) ◽  
pp. 435-454 ◽  
Author(s):  
BJØRN IAN DUNDAS ◽  
AYELET LINDENSTRAUSS ◽  
BIRGIT RICHTER
Keyword(s):  
Hochschild Homology ◽  
Second Order ◽  
Ring Spectra ◽  
Quotient Maps ◽  
Local Complex ◽  
K Theory ◽  
Tame Ramification ◽  
Topological Hochschild Homology

AbstractWe propose topological Hochschild homology as a tool for measuring ramification of maps of structured ring spectra. We determine second order topological Hochschild homology of the p-local integers. For the tamely ramified extension of the map from the connective Adams summand to p-local complex topological K-theory we determine the relative topological Hochschild homology and show that it detects the tame ramification of this extension. We show that the complexification map from connective topological real to complex K-theory shows features of a wildly ramified extension. We also determine relative topological Hochschild homology for some quotient maps with commutative quotients.

scholarly journals Eliminating tame ramification : generalizations of Abhyankar’s lemma

2020 ◽  
Vol 307 (1) ◽  
pp. 121-136
Author(s):  
Arpan Dutta ◽  
Franz-Viktor Kuhlmann
Keyword(s):  
Tame Ramification

scholarly journals Geometric Langlands correspondence for , over the pair of pants

2019 ◽  
Vol 155 (2) ◽  
pp. 324-371 ◽  
Author(s):  
David Nadler ◽  
Zhiwei Yun
Keyword(s):  
Projective Line ◽  
Langlands Correspondence ◽  
Geometric Langlands ◽  
Rank One ◽  
Tame Ramification

We establish the geometric Langlands correspondence for rank-one groups over the projective line with three points of tame ramification.

The Schur Subgroup of a p-Adic Field

1979 ◽  
Vol 31 (2) ◽  
pp. 300-303
Author(s):  
Eugene Spiegel ◽  
Allan Trojan
Keyword(s):  
Finite Group ◽  
Simple Group ◽  
Group Algebras ◽  
Brauer Group ◽  
Ramification Index ◽  
Simple Component ◽  
Image Position ◽  
Cyclotomic Algebras ◽  
A Finite Group ◽  
Tame Ramification

Let K be a field. The Schur subgroup, S(K), of the Brauer group, B(K), consists of all classes [△] in B(K) some representative of which is a simple component of one of the semi-simple group algebras, KG, where G is a finite group such that char K ∤ G. Yamada ([11], p. 46) has characterized S(K) for all finite extensions of the p-adic number field, Qp. If p is odd, [△] ∈ S(K) if and only ifwhere c is the tame ramification index of k/Qp, k the maximal cyclotomic subfield of K, and s = ((p – 1)/c, [K : k]). invp △ is the Hasse invariant. Yamada showed this by proving first that S(K) is the group of classes containing cyclotomic algebras and then determining the invariants of such algebras.

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