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Finitely generated GEn-rings

Published online by Cambridge University Press:  14 November 2011

A. W. Mason
Affiliation:
Department of Mathematics, The University, Glasgow G12 8QW, U.K.

Synopsis

Suslin and Cohn have proved that the polynomial ring Z[t1, …,td], where Z is the ring of rational integers and d >0, is a GEn-ring if and only if n ≧ 3. (A commutative ring R with identity is called a GEn-ring if and only if SLn(R) is generated by elementary matrices, where n ≧ 2.) In this paper we consider the following question:

Given algebraic numbers α1, …,αd, for which n (if any) is the ring A =Z [α1, …,αd a GEn-ring?

By standard results from algebraic K-theory it follows that (a) A is GEn for all n ≧ 2, (b) A is not GEn for any n ≧ 2, or (c) A is GEn if and only if n ≧ 3. Examples of each type are provided. In particular, it is shown that if each αi is real or at least one αi is not an algebraic integer, then A is of type (a).

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1987

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References

1Bachmuth, S. and Mochizuki, H.. E 2 ≠ SL2 for most Laurent polynomial rings. Amer. 1. Math. 104 (1982), 11811189.Google Scholar
2Bass, H.. Algebraic K-theory (New York: Benjamin, 1968).Google Scholar
3Bass, H., Milnor, J. and Serre, J.-P.. Solution of the congruence subgroup problem for SL n (n ≥3) and SP 2n (n ≥2). Inst. Hautes Études Sci. Publ. Math. 33 (1967), 59137.Google Scholar
4Cohn, P. M.. On the structure of the GL 2 of a ring. Inst. Hautes Études Sci. Publ. Math. 30 (1966), 365413.CrossRefGoogle Scholar
5Liehl, B.. On the group SL 2 over orders of arithmetic type. J. Reine Angew. Math. 323 (1981), 153171.Google Scholar
6Mason, A. W. and Stothers, W. W.. On subgroups of GL(n, A) which are generated by commutators. Invent. Math. 23 (1974), 327346.Google Scholar
7Rankin, R. A.. Modular forms and functions (Cambridge: Cambridge University Press, 1977).CrossRefGoogle Scholar
8Ribenboim, P.. Algebraic numbers (New York: Wiley-Interscience, 1972).Google Scholar
9Suslin, A. A.. On the structure of the special linear group over polynomial rings. Math. USSR-Izv. 11 (1977), 221238.CrossRefGoogle Scholar