TITLE

# 8-ranks of Class Groups of Some Imaginary Quadratic Number Fields

AUTHOR(S)
Xi Mei Wu; Qin Yue
PUB. DATE
November 2007
SOURCE
Acta Mathematica Sinica;Nov2007, Vol. 23 Issue 11, p2061
SOURCE TYPE
DOC. TYPE
Article
ABSTRACT
Let $$F = \mathbb{Q}{\left( {{\sqrt { - p_{1} p_{2} } }} \right)}$$ be an imaginary quadratic field with distinct primes p 1 â‰¡ p 2 â‰¡ 1 mod 8 and the Legendre symbol $${\left( {\frac{{p_{1} }} {{p_{2} }}} \right)} = 1$$ . Then the 8-rank of the class group of F is equal to 2 if and only if the following conditions hold: (1) The quartic residue symbols $${\left( {\frac{{p_{1} }} {{p_{2} }}} \right)}_{4} = {\left( {\frac{{p_{2} }} {{p_{1} }}} \right)}_{4} = 1$$ ; (2) Either both p 1 and p 2 are represented by the form a 2 +32 b 2 over â„¤ and $$p^{{h_{ + } {\left( {2p_{1} } \right)}/4}}_{2} = x^{2} - 2p_{1} y^{2} ,x,y \in \mathbb{Z}$$ , or both p 1 and p 2 are not represented by the form a 2 +32 b 2 over â„¤ and $$p^{{h_{ + } {\left( {2p_{1} } \right)}/4}}_{2} = \varepsilon {\left( {2x^{2} - p_{1} y^{2} } \right)},\;x,y \in \mathbb{Z},\;\varepsilon \in {\left\{ { \pm 1} \right\}}$$ , where h +(2 p 1) is the narrow class number of $$\mathbb{Q}{\left( {{\sqrt {2p_{1} } }} \right)}$$ . Moreover, we also generalize these results.
ACCESSION #
27251548

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