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The characteristic ring and the “best” way to adjoin a one

Published online by Cambridge University Press:  09 April 2009

W. D. Burgess
Affiliation:
Department of Mathematics, University of OttawaOttawa, OntarioCanadaK1N 6N5
P. N. Stewart
Affiliation:
Department of Mathematics, Statistics and Computing Science, Dalhousie UniversityHalifax, Nova ScotiaCanadaB3H 3J5
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Abstract

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For any ring S we define and describe its characteristic ring, k(S). It plays the rôle of the usual characteristic even in rings whose additive structure, (S, +), is complicated. The ring k(S) is an invariant of (S, +) and also reflects certain non-additive properties of S. If R is a left faithful ring without identity element, we show how to use k(R) to embed R in a ring R1 with identity. This unital overring of R inherits many ring properties of R; for instance, if R is artinian, noetherian, semiprime Goldie, regular, biregular or a V-ring, so too is R1. In the case of regularity (or generalizations thereof), R1 satisfies a universal property with respect to the adjunction of an identity

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1989

References

[1]Bousfield, A. K. and Kan, D. M., ‘The core of a ring’, J. Pure Appl. Algebra 2 (1972), 7381.CrossRefGoogle Scholar
[2]Burgess, W. D. and Menal, P., ‘Strongly π–regu1ar rings and homomorphisms into them’, Comm. Algebra 16 (1988), 17011725.CrossRefGoogle Scholar
[3]Cheatham, T. and Enochs, E., ‘The epimorphic images of a Dedekind domain’, Proc. Amer. Math. Soc. 35 (1972), 3742.CrossRefGoogle Scholar
[4]Dauns, J. and Hofmann, K. H., ‘The representation of biregular rings by sheaves’, Math. Z. 91 (1966), 103123.CrossRefGoogle Scholar
[5]Dicks, W. and Stephenson, W., ‘Epimorphs and dominions of Dedekind domains’, J. London Math. Soc. 29 (1984), 224228.CrossRefGoogle Scholar
[6]Feigelstock, S., ‘An embedding theorem for weakly regular and fully idempotent rings’, Comment. Math. Univ. St. Paul 27 (1978), 101103.Google Scholar
[7]Fuchs, L., Abelian groups (Pergamon Press, Oxford, 1960).Google Scholar
[8]Fuchs, L. and Halperin, I., ‘On the imbedding of a regular ring in a regular ring with identity’, Fund. Math. 54 (1964), 285290.CrossRefGoogle Scholar
[9]Fuchs, L. and Rangaswamy, K. M., ‘On generalized regular rings’, Math. Z. 107 (1968), 7181.CrossRefGoogle Scholar
[10]Goodearl, K. R., Von Neumann regular rings (Pitman, London, 1979).Google Scholar
[11]Gordon, R. and Robson, J. C., ‘Krull dimension’, Mem. Amer. Math. Soc. 133 (1973).Google Scholar
[12]Koh, K., Quasisimple modules and other topics in ring theory (Lecture Notes in Math. 246 (1972), 323428).CrossRefGoogle Scholar
[13]Michler, G. and Villamayor, O., ‘On rings whose simple modules are injective,’ J. Algebra 25 (1973), 185201.CrossRefGoogle Scholar
[14]Robson, J. C., ‘A unified approach to unity,’ Comm. Algebra 7 (1979), 12451255.CrossRefGoogle Scholar
[15]Rosenberg, A. and Zelinsky, D., ‘On the finiteness of the injective hull,’ Math. Z. 70 (1959), 372380.CrossRefGoogle Scholar
[16]Storrer, H. H., ‘Epimorphismen von kommutativen Ringen’, Comment Math. Helv. 43 (1968), 378401.CrossRefGoogle Scholar
[17]Storrer, H. H., ‘Epimorphic extensions of non-commutative rings’, Comment. Math. Helv. 48 (1973), 7286.CrossRefGoogle Scholar
[18]Vrabec, J., ‘Adjoining a unit to a biregular ring’, Math. Ann. 188 (1970), 219226.CrossRefGoogle Scholar