The associated orders of rings of integers in Lubin-Tate division fields over the \(p\)-adic number field
The associated order of a Galois extension \(L/K\) is the subset \(\{\lambda\in K[\Gamma ]\mid \lambda{\mathcal O}_ L \subseteq{\mathcal O}_ L\}\) of the group ring \(K[\Gamma ]\), where \(\Gamma= \text{Gal} (L/K)\), \({\mathcal O}_ L\) is the valuation ring (if \(L\) is local) or the ring of integers (if \(L\) is global). Let \(\mathbb{Q}_ p\) denote the \(p\)-adic number field, \(\mathbb{Q}^ n_{p,\pi}\) the division field of level \(n\) and uniformizer \(\pi\) associated to some Lubin-Tate formal group. The authors determine the generators of the associated order of \(L/K\) with \(L= \mathbb{Q}_{p,\pi}^{m+r}\), \(K= \mathbb{Q}^ r_{p,\pi}\). This work is based on the authors' former work [J. Reine Angew. Math. 434, 205-220 (1993; Zbl 0753.11038)], by adjoining an unramified extension to \(K\) to obtain a relative cyclotomic extension and descending then to \(\mathbb{Q}_ p\).
scientific article; zbMATH DE number 711023