Local units modulo circular units
Local units modulo circular units
复制标题
局部单位模圆单位
DOI:
10.1090/s0002-9939-1983-0706497-1
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发表时间:
1983
影响因子:
2.5
通讯作者:
R. Coleman
中科院分区:
文献类型:
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作者:
R. Coleman
In his paper, Some Modules in the Theorv of Cyclotomic Fields [2], Iwasawa obtained the remarkable theorem that the quotient of the p-adic cyclotomic units by the completion of the circular units is isomorphic to the quotient of the group ring by the Stickleberger ideal. He then used this to deduce some interesting global results, the most striking of which is an explanation of the plus part of the analytic class number formula under the assumption that the class group at the first layer is cyclic, together with a regularity assumption. In this note, we will show how with the results in our paper, Division Values in Local Fields [1], it is now possible to give a substantially simpler proof of the above theorem. We also describe, briefly, how one can obtain various global results of Iwasawa from this Theorem, which are not included in either Lang's [3], or Washington's [4] books. I. Notation. Let Qp((T)) denote the ring of Laurent series with finite poles over Qp. Let Qp((T)), and Qp[[T]], denote the subrings of Qp((T)) consisting of power series which converge on the punctured open unit ball and on the open unit ball respectively. Let Zp((T)) denote the subring of Qp((T)) with integer coefficients and Zp[[T]] the ring Zp((T)) n Qp[[T]],. Let S and DL denote the trace and norm operators defined in [1] on Qp((T)), and Zp((T))* respectively. They are characterized by the formulas (1) 5(g)(l(I -T)p) = ]Eg(l (l -T)), (2) DL(f)(I (I-T)p) = Ilf(I t(l-T))l where ; runs over the pth roots of unity tp. Let [a](T) = 1 -(1-T) 9g go [p], D (I T) dT f Df for g FE Qp[[T]] l andf E Z ((T))* We then have the identities (3) SLog(f) Log(Lf), (4) SDg = pD$g, (5) 58(h) = p89(h), (6) ST(g) = Pm Received by the editors September 20, 1982 and, in revised form, December 20, 1982. 1980 Mathematics Subject Classification. Primary 12A35. (1983 American Mathematical Society 0002-9939/82/0000-1451 /$03.00