Czechoslovak Mathematical Journal, Vol. 73, No. 3, pp. 937-940, 2023
On the class number of the maximal real subfields of a family of cyclotomic fields
Mahesh Kumar Ram
Received August 24, 2022. Published online April 27, 2023.
Abstract: For any square-free positive integer $m\equiv{10}\pmod{16}$ with $m\geq26$, we prove that the class number of the real cyclotomic field $\mathbb{Q}(\zeta_{4m}+\zeta_{4m}^{-1})$ is greater than $1$, where $\zeta_{4m}$ is a primitive $4m$th root of unity.
Keywords: maximal real subfield of cyclotomic field; real quadratic field; class number
Affiliations: Mahesh Kumar Ram, Indian Institute of Science Education and Research, Govt. ITI Building Engg. School Junction, Brahmapur, Odisha 760010, India, e-mail: maheshk@iiserbpr.ac.in