A modular construction of unramifiedp-extensions ofQ(μp)
A modular construction of unramifiedp-extensions ofQ(μp)
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DOI:
10.1007/bf01403065
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发表时间:
1976-10
影响因子:
3.1
通讯作者:
K. Ribet
中科院分区:
文献类型:
--
作者:
K. Ribet
An odd prime p is called irregular if the class number of the field Q (# p) is divisible by p (# p being, as usual, the group of p-th roots of unity). According to Kummer's criterion, p is irregular if and only if there exists an even integer k with 2_< k_< p-3 such that p divides (the numerator of) the k-th Bernoulli number Bk, given by the expansion t t 1 B, t. e t-1~-2-= n>=~ 2 n!" The purpose of this paper is to strengthen Kummer's criterion. Let A be the ideal class group of Q (#~), and let C be the Fp-vector space A/A p. The Galois group Gal (0/Q) acts on C through its quotient A= GaI (Q (~ p)/Q). Since all characters of A with values in 1~* are powers of the standard character