Formal completions of Néron models for algebraic tori
arXiv:0704.2578 · doi:10.1112/plms/pdp039
Abstract
We calculate the formal group law which represents the completion of the Néron model of an algebraic torus over the rationals that splits in a tamely ramified abelian extension. As a tools in the proof, we define and give criterions to compute the Weil restriction of a formal group law and the analog of the fixed part of a formal group law with respect to the action of a (finite) group.
arXiv comment35 pages. New version with new functoriality results. Final version in the Proceedings of the London Mathematical Society, link: http://plms.oxfordjournals.org/cgi/content/abstract/pdp039?ijkey=NVyJlz51HbzrzxM&keytype=ref