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On n-flat modules over a commutative ring

Published online by Cambridge University Press:  17 April 2009

David E. Dobbs
Affiliation:
Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1300, United States of America
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Abstract

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Let R be a commutative ring with unit, T an R-module, and n a positive integer. It is proved that T is n-flat over R if BRT is B-torsionfree for each n–generated commutative R-algebra B. The converse holds if T is n–generated, in which case T is actually flat over R. Several other instances of the converse are established, but it is shown that the converse fails in general, even for R an integral domain, T an ideal of R, and n = 1.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1991

References

[1]Akiba, T., LCM-stableness, Q-stableness and flatness, Kobe J. Math. 2 (1985), 6770.Google Scholar
[2]Anderson, D.D. and Dobbs, D.E., ‘Flatness, LCM-stability, and related module-theoretic properties’, J. Algebra 112 (1988), 139150.CrossRefGoogle Scholar
[3]Bourbaki, N., Commutative Algebra (Addison-Wesley, Reading, 1972).Google Scholar
[4]Chase, S.U., ‘Direct products of modules’, Trans. Amer. Math. Soc. 97 (1960), 457473.CrossRefGoogle Scholar
[5]Davis, E.D., ‘A remark on Prüfer rings’, Proc. Amer. Math. Soc. 20 (1969), 235237.Google Scholar
[6]Dobbs, D.E., ‘On the weak global dimension of pseudo-valuation domains’, Canad. Math. Bull. 21 (1978), 159164.CrossRefGoogle Scholar
[7]Dobbs, D.E., ‘On flat finitely generated ideals’, Bull. Austral. Math. Soc. 21 (1980), 131135.CrossRefGoogle Scholar
[8]Dobbs, D.E., ‘On the criteria of D.D. Anderson for invertible and flat ideals’, Canad. Math. Bull. 29 (1986), 2532.CrossRefGoogle Scholar
[9]Gilmer, R., Finite element factorization in group rings: Lecture Notes in Pure and Appl. Math. 7 (Dekker, New York, 1974).Google Scholar
[10]Hattori, A., ‘On Prüfer rings’, J. Math. Soc. Japan 9 (1957), 381385.CrossRefGoogle Scholar
[11]Hedstrom, J.R. and Houston, E.G., ‘Pseudo-valuation domains’, Pacific J. Math. 75 (1978), 137147.CrossRefGoogle Scholar
[12]Lazarus, M., ‘Fermeture intégrale et changement de base’, Ann. Fac. Sci. Toulouse Math. 6 (1984), 103120.CrossRefGoogle Scholar
[13]Richman, F., ‘Generalized quotient rings’, Proc. Amer. Math. Soc. 16 (1965), 794799.CrossRefGoogle Scholar
[14]Sato, J. and Yoshida, K., ‘The LCM-stability on polynomial extensions’, Math. Rep. Toyama Univ. 10 (1987), 7584.Google Scholar
[15]Uda, H., ‘LCM-stableness in ring extensions’, Hiroshima Math. J. 13 (1983), 357377.CrossRefGoogle Scholar
[16]Uda, H., ‘G 2-stableness and LCM-stableness’, Hiroshima Math. J. 18 (1988), 4752.CrossRefGoogle Scholar