English

The canonical dimension of modules for Iwasawa algebras

Number Theory 2025-12-18 v2 Rings and Algebras Representation Theory

Abstract

Let F be a non-trivial finite extension of the p-adic numbers, and G be a compact p-adic Lie group whose Lie algebra is isomorphic to a split semisimple F-Lie algebra. We prove that the mod p Iwasawa algebra of G has no modules of canonical dimension one. One consequence is a new upper bound on the Krull dimension of the Iwasawa algebra. We also prove a canonical dimension-theoretic criterion for a mod p smooth admissible representation to be of finite length. Combining our results shows that any smooth admissible representation of GLn(F)GL_n(F), with central character, has finite length if its dual has canonical dimension two.

Keywords

Cite

@article{arxiv.2306.09696,
  title  = {The canonical dimension of modules for Iwasawa algebras},
  author = {James Timmins},
  journal= {arXiv preprint arXiv:2306.09696},
  year   = {2025}
}

Comments

37 pages. Primary results extended to semisimple Lie algebras. Section 7 rewritten to give an improved statement. Section 8 expanded to improve an abstract bound on Krull dimension. Section 9 shortened by a new proof that holonomic representations are of finite length. Minor corrections and edits throughout. Acknowledgements updated. Manuscript accepted in Selecta Mathematica