New ramification breaks and additive Galois structure
Journal de théorie des nombres de Bordeaux, Volume 17 (2005) no. 1, pp. 87-107.

Which invariants of a Galois p-extension of local number fields L/K (residue field of char p, and Galois group G) determine the structure of the ideals in L as modules over the group ring p [G], p the p-adic integers? We consider this question within the context of elementary abelian extensions, though we also briefly consider cyclic extensions. For elementary abelian groups G, we propose and study a new group (within the group ring 𝔽 q [G] where 𝔽 q is the residue field) and its resulting ramification filtrations.

Quels invariants d’une p-extension galoisienne de corps local L/K (de corps résiduel de charactéristique p et groupe de Galois G) déterminent la structure des idéaux de L en tant que modules sur l’anneau de groupe p [G], p l’anneau des entiers p-adiques ? Nous considérons cette question dans le cadre des extensions abéliennes élémentaires, bien que nous considérions aussi brièvement des extensions cycliques. Pour un groupe abélien élémentaire G, nous proposons et étudions un nouveau groupe (dans l’anneau de groupe 𝔽 q [G]𝔽 q est le corps résiduel) ainsi que ses filtrations de ramification.

DOI: 10.5802/jtnb.479

Nigel P. Byott 1; G. Griffith Elder 2

1 Department of Mathematical Sciences University of Exeter Exeter EX4 4QE United Kingdom
2 Department of Mathematics University of Nebraska at Omaha Omaha, NE 68182-0243 U.S.A.
@article{JTNB_2005__17_1_87_0,
     author = {Nigel P. Byott and G. Griffith Elder},
     title = {New ramification breaks and additive {Galois} structure},
     journal = {Journal de th\'eorie des nombres de Bordeaux},
     pages = {87--107},
     publisher = {Universit\'e Bordeaux 1},
     volume = {17},
     number = {1},
     year = {2005},
     doi = {10.5802/jtnb.479},
     mrnumber = {2152213},
     zbl = {1162.11394},
     language = {en},
     url = {https://jtnb.centre-mersenne.org/articles/10.5802/jtnb.479/}
}
TY  - JOUR
AU  - Nigel P. Byott
AU  - G. Griffith Elder
TI  - New ramification breaks and additive Galois structure
JO  - Journal de théorie des nombres de Bordeaux
PY  - 2005
SP  - 87
EP  - 107
VL  - 17
IS  - 1
PB  - Université Bordeaux 1
UR  - https://jtnb.centre-mersenne.org/articles/10.5802/jtnb.479/
DO  - 10.5802/jtnb.479
LA  - en
ID  - JTNB_2005__17_1_87_0
ER  - 
%0 Journal Article
%A Nigel P. Byott
%A G. Griffith Elder
%T New ramification breaks and additive Galois structure
%J Journal de théorie des nombres de Bordeaux
%D 2005
%P 87-107
%V 17
%N 1
%I Université Bordeaux 1
%U https://jtnb.centre-mersenne.org/articles/10.5802/jtnb.479/
%R 10.5802/jtnb.479
%G en
%F JTNB_2005__17_1_87_0
Nigel P. Byott; G. Griffith Elder. New ramification breaks and additive Galois structure. Journal de théorie des nombres de Bordeaux, Volume 17 (2005) no. 1, pp. 87-107. doi : 10.5802/jtnb.479. https://jtnb.centre-mersenne.org/articles/10.5802/jtnb.479/

[1] M. V. Bondarko, Links between associated additive Galois modules and computation of H 1 for local formal group modules. J. Number Theory 101 (2003), 74–104. | MR | Zbl

[2] N. P. Byott, G. G. Elder, Biquadratic extensions with one break. Can. Math. Bull. 45 (2002), 168–179. | MR | Zbl

[3] G. G. Elder, Galois module structure of integers in wildly ramified cyclic extensions of degree p 2 . Ann. Inst. Fourier (Grenoble) 45 (1995), 625–647; errata ibid. 48 (1998), 609–610. | Numdam | MR | Zbl

[4] G. G. Elder, Galois module structure of ambiguous ideals in biquadratic extensions. Can. J. Math. 50 (1998), 1007–1047. | MR | Zbl

[5] G. G. Elder, On the Galois structure of the integers in cyclic extensions of local number fields. J. Théor. Nombres Bordeaux. 14 (2002), 113–149. | Numdam | MR | Zbl

[6] G. G. Elder, The Galois module structure of ambiguous ideals in cyclic extensions of degree 8. To appear in the Proceedings of the International Algebraic Conference dedicated to the memory of Z. I. Borevich, Sept 17–23, 2002.

[7] R. L. Graham, D. E. Knuth, O. Patashnik, Concrete Mathematics: A Foundation for Computer Science. Addison Wesley, Reading MA 1989. | MR | Zbl

[8] J. V. Kuzmin, Representations of finite groups by automorphisms of nilpotent near spaces and by automorphisms of nilpotent groups. Sibirsk. Mat. Ž. 13 (1972), 107–117. | MR | Zbl

[9] J-P. Serre, Local Fields. Springer-Verlag, New York, 1979. | MR | Zbl

[10] A. Weiss, Rigidity of p-adic p-torsion. Ann. of Math. (2) 127 (1988), 317–332. | MR | Zbl

[11] B. Wyman, Wildly ramified gamma extensions. Amer. J. Math. 91 (1969), 135–152. | MR | Zbl

Cited by Sources: