On imaginary quadratic fields with non-cyclic class groups

被引:0
作者
Ouyang, Yi [1 ,2 ]
Song, Qimin [1 ]
Zhang, Chenhao [1 ]
机构
[1] Univ Sci & Technol China, Sch Math Sci, Wu Wen Tsun Key Lab Math, Hefei 230026, Anhui, Peoples R China
[2] Univ Sci & Technol China, Hefei Natl Lab, Hefei 230088, Peoples R China
关键词
Class numbers; Imaginary quadratic fields; Ideal class group; CLASS-NUMBERS;
D O I
10.1007/s11139-025-01154-y
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
For a fixed abelian group H, let NH (X) be the number of square-free positive integers d <= X such that H <= CL(Q(root-d)). We obtain asymptotic lower bounds for NH (X) as X -> infinity in two cases: H = Z/g(1)Z x (Z/2Z)(l) for l >= 2 and 2 inverted iota g(1) >= 3, H = (Z/gZ)(2) for 2 inverted iota g >= 5. More precisely, for any epsilon > 0, we show N-H(X) >> X1/2+ 3/ 2g1+2-epsilon when H = Z/g(1)Z x (Z/2Z)(l) for l >= 2 and 2 inverted iota g(1) >= 3. For the second case, under a well known conjecture for square-free density of integral multivariate polynomials, for any epsilon > 0, we show N-H(X) >> X1/ 8-1-epsilon. When H =(Z/gZ)(2) for odd g >= 5. The first case is an adaptation of Soundararajan's results for H = Z/gZ, 1 and the second conditionally improves the X1/g-epsilon due to Byeon and the bound X-1/g /(log X)(2) due to Kulkarni and Levin.
引用
收藏
页数:8
相关论文
共 12 条
[1]  
Ankeny N., 1955, Pac. J. Math, V5, P321, DOI DOI 10.2140/PJM.1955.5.321
[2]   Imaginary quadratic fields with noncyclic ideal class groups [J].
Byeon, Dongho .
RAMANUJAN JOURNAL, 2006, 11 (02) :159-163
[3]   On the p-ranks of the ideal class groups of imaginary quadratic fields [J].
Chattopadhyay, Jaitra ;
Saikia, Anupam .
RAMANUJAN JOURNAL, 2023, 62 (02) :571-581
[4]  
COHEN H, 1984, LECT NOTES MATH, V1068, P33
[5]  
Heath-Brown R, 2007, FUNCT APPROX COMMENT, V37, P203
[6]  
Honda T., 1960, Jpn. J. Math, V30, P84
[7]   Hilbert's Irreducibility Theorem and ideal class groups of quadratic fields [J].
Kulkarni, Kaivalya R. ;
Levin, Aaron .
ACTA ARITHMETICA, 2022, 205 (04) :371-380
[8]  
Murty MR., 1997, Exponents of Class Groups of Quadratic Fields, Topics in Number Theory, Mathematics and Its Applications, V467, P229
[9]   Squarefree values of multivariable polynomials [J].
Poonen, B .
DUKE MATHEMATICAL JOURNAL, 2003, 118 (02) :353-373
[10]   Divisibility of class numbers of imaginary quadratic fields [J].
Soundararajan, K .
JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES, 2000, 61 :681-690