English

Reciprocity maps with restricted ramification

Number Theory 2022-02-01 v3

Abstract

We compare two maps that arise in study of the cohomology of number fields with ramification restricted to a finite set S of primes. One of these maps, which we call an S-reciprocity map, interpolates the values of cup products in S-ramified cohomology. In the case of p-ramified cohomology of the pth cyclotomic field for an odd prime p, we use this to exhibit an intriguing relationship between particular values of the cup product on cyclotomic p-units. We then consider higher analogues of the S-reciprocity map and relate their cokernels to the graded quotients in augmentation filtrations of Iwasawa modules.

Keywords

Cite

@article{arxiv.1609.03616,
  title  = {Reciprocity maps with restricted ramification},
  author = {Romyar T. Sharifi},
  journal= {arXiv preprint arXiv:1609.03616},
  year   = {2022}
}

Comments

40 pages, replaced last section (original may appear separately), to appear in Trans. Amer. Math. Soc

R2 v1 2026-06-22T15:47:44.669Z