On the index divisors of certain number fields of degree ten defined by
Volume 176 / 2024
Abstract
For any number field K generated by a root \alpha of a monic irreducible trinomial F(x)=x^{10}+ax^m+b \in \mathbb Z[x] with 1\leq m\leq 9 and for every rational prime p, we give sufficient conditions which guarantee that p divides the index of K. We also calculate \nu _p(i(K)) in each case. For m=1, we show that the index of K is either 1 or a power of 3 for any (a,b)\in \mathbb Z^2, and we characterize when 3 divides i(K). As an application, we show that if i(K)\neq 1, then K is not monogenic. We illustrate our results by some computational examples.