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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2014 Volume 429, Pages 193–201 (Mi znsl6075)

On the class numbers of algebraic number fields

O. M. Fomenko

St. Petersburg Department of V. A. Steklov Institute of Mathematics of the Russian Academy of Sciences, St. Petersburg, Russia

Abstract: Let $K$ be a number field of degree $n$ over $\mathbb Q$ and $d,h$, and $R$ be the absolute value of the discriminant, the class number, and the regulator, respectively, of $K$. It is known that if $K$ contains no quadratic subfield, then
$$ hR\gg\frac{d^{1/2}}{\log d}, $$
where the implied constant depends only on $n$. In Theorem 1 this lower estimate is improved for pure cubic fields.
Consider the family $\mathcal K_n$ where $K\in\mathcal K_n$ if $K$ is a totally real number field of degree $n$ whose normal closure has the symmetric group $S_n$ as its Galois group. Theorem 2: Fix $n\ge2$. There are infinitely many $K\in\mathcal K_n$ with
$$ h\gg d^{1/2}(\log\log d)^{n-1}/(\log d)^n, $$
where the implied constant depends only on $n$.
This is a somewhat greater improvement over W. Duke's analogous result with $h\gg d^{1/2}/(\log d)^n$ [MR 1966783 (2004g:11103)].

Key words and phrases: class number, Dedekind $\zeta$-function, generalized Riemann hypothesis.

UDC: 511.466+517.863

Received: 15.07.2012


 English version:
Journal of Mathematical Sciences (New York), 2015, 207:6, 934–939

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© Steklov Math. Inst. of RAS, 2024