Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-16T15:19:46.715Z Has data issue: false hasContentIssue false

Recursively presented Abelian groups: Effective p-Group theory. I

Published online by Cambridge University Press:  12 March 2014

Charlotte Lin*
Affiliation:
Schlumberger-Doll Research, Ridgefield, Connecticut 06877

Extract

The study of effectiveness in classical mathematics is rapidly expanding, through recent research in algebra, topology, model theory, and functional analysis. Well-known contributors are Barwise (Wisconsin), Crossley (Monash), Dekker (Rutgers), Ershoff (Novosibirsk), Feferman (Stanford), Harrington (Berkeley), Mal′cev (Novosibirsk), Morley (Cornell), Nerode (Cornell), Rabin (Hebrew University), Shore (Cornell). Further interesting work is due to Kalantari (University of California, Santa Barbara), Metakides (Rochester), Millar (Wisconsin), Remmel (University of California, San Diego), Nurtazin (Novosibirsk). Areas investigated include enumerated algebras, models of complete theories, vector spaces, fields, orderings, Hilbert spaces, and boolean algebras.

We investigate the effective content of the structure theory of p-groups. Recall that a p-group is a torsion abelian group in which the (finite) order of each element is some power of a fixed prime p. (In the sequel, “group” = “additively written abelian group”.)

The structure theory of p-groups is based on the two elementary notions of order and height. Recall that the order of x is the least integer n such that nx = 0. The height of x is the number of times p divides x, that is, the least n such that x = pny for some y in the group but xpn+1y for any y. If for each nω there is a “pnth-root” yn, so that x = pnyn, then we say that x has infinite height. In 1923, Prüfer related the two notions as criteria for direct sum decomposition, proving

Theorem. Every group of bounded order is a direct sum of cyclic groups, and

Theorem. Every countable primary group with no (nonzero) elements of infinite height is a direct sum of cyclic groups.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1981

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

BIBLIOGRAPHY

[1]Barwise, J. and Eklof, P., Infinitary properties of abelian torsion groups, Annals of Mathematical Logic, vol. 4 (1970), pp. 2568.CrossRefGoogle Scholar
[2]Crossley, J. N. and Nerode, A., Effective dimension, Journal of Algebra (to appear).Google Scholar
[3]Dekker, J. C. E., Countable vector spaces with recursive operations. Part I, this Journal, vol. 34 (1969), pp. 363387.Google Scholar
[4]Dekker, J. C. E., Countable vector spaces with recursive operations. Part II, this Journal, vol. 36 (1971), pp. 477495.Google Scholar
[5]Ekloff, P. C. and Fischer, E. R., The elementary theory of abelian groups, Annals of Mathematical Logic, vol. 4(1972), pp. 115171.CrossRefGoogle Scholar
[6]Feferman, S., Impredicativity of the existence of the largest divisible subgroup of an abelian p-group, Lecture Notes in Mathematics, no. 498, Springer-Verlag, Berlin, 1975, pp. 117130.Google Scholar
[7]Frohlich, A. and Sheperdson, J. C., Effective procedures in field theory, Philosophical Transactions of the Royal Society of London, Section A, vol. 284 (1955), pp. 407432.Google Scholar
[8]Fuchs, L., Abelian groups, Pergamon Press, Budapest, 1958.Google Scholar
[9]Harrington, L., Recursively presentable prime models, mimeograph, 1972.Google Scholar
[10]Kalantari, I. and Retzlaff, A., Maximal vector spaces under automorphisms of the lattice of recursively enumerable sets, this Journal, vol. 42 (1977), pp. 481491.Google Scholar
[11]Kaplansky, I., Infinite abelian groups, University of Michigan Press, Ann Arbor, 1969.Google Scholar
[12]Kulikov, L., Zur Theorie der abelschen Gruppen von beliebiger Mächtigheit, Matematičeskit Sborniǐ, vol. 9 (1941), pp. 165181. (Russian with German summary)Google Scholar
[13]Kulikov, L., K teorii abelevych grupp proizvolnoi moščnosti, Matematičeskiǐ Sbornik, vol. 16 (1945), pp. 129162. (Russian with English summary)Google Scholar
[14]Lin, C., The effective content of Ulm's theorem. Effective aspects of algebra, Upside-Down A Book Company, Yarra Glenn, 1981.Google Scholar
[15]Lin, C., Recursively presented abelian groups: Effective p-group theory. II (to appear).Google Scholar
[16]Metakides, G. and Nerode, A., Recursion theory and algebra, Algebra and Logic, Lecture Notes in Mathematics, no. 450, Springer-Verlag, Berlin and New York, 1975, pp. 209220.CrossRefGoogle Scholar
[17]Metakides, G. and Nerode, A., Recursively enumerable vector spaces, Annals of Mathematical Logic, vol. 11 (1977), pp. 147171.CrossRefGoogle Scholar
[18]Millar, T., Foundations of recursive model theory, this Journal (to appear).Google Scholar
[19]Millar, T., A complete decidable theory with two recursively presentable models, this Journal, vol. 44 (1979), pp. 307312.Google Scholar
[20]Prüfer, H., Untersuchungen über die Zerlegbarkeit der abzählbaren primären abelschen Gruppen, Mathematische Zeitschrift, vol. 17 (1923), pp. 3561.CrossRefGoogle Scholar
[21]Rabin, M. O., Computable algebra, general theory and theory of computable fields, Transactions of the American Mathematical Society, vol. 95 (1960), pp. 341360.Google Scholar
[22]Remmel, J., Co-recursively enumerable structures, Ph.D. dissertation, Cornell University, 1974.Google Scholar
[23]Richman, F., The constructive theory of abelian p-groups, Pacific Journal of Mathematics, vol. 45 (1973), pp. 621637.CrossRefGoogle Scholar
[24]Shore, R., Controlling the dependence degree of a recursively enumerable vector space, this Journal, vol. 43 (1978), pp. 1322.Google Scholar
[25]Smith, R., The theory of profinite groups with effective presentations, Ph.D. dissertation, Pennsylvania State University, University Park, 1979.Google Scholar