I argue for the use of the adjunction operator (adding a single
new element to an existing set) as a basis for building a finitary
set theory. It allows a simplified axiomatization for the
first-order theory of hereditarily finite sets based on an
induction schema and a rigorous characterization of the primitive
recursive set functions. The latter leads to a primitive
recursive presentation of arithmetical operations on finite
sets.
References
[1] Ackermann, W., "Die Widerspruchsfreiheit der allgemeinen Mengenlehre", Mathematische Annalen, vol. 114 (1937), pp. 305--15.
[2] Avigad, J., "Saturated models of universal theories", Annals of Pure and Applied Logic, vol. 118 (2002), pp. 219--34.
[3] Ferreira, F., "A simple proof of Parsons' theorem", Notre Dame Journal of Formal Logic, vol. 46 (2005), pp. 83--91.
[4] Forster, T., Logic, Induction and Sets, vol. 56 of London Mathematical Society Student Texts, Cambridge University Press, Cambridge, 2003.
[5] Garcia, N., "Operating on the universe", Archive for Mathematical Logic, vol. 27 (1988), pp. 61--68.
Mathematical Reviews (MathSciNet):
MR955312
[6] Givant, S., and A. Tarski, "Peano arithmetic and the Zermelo-like theory of sets with finite ranks", Notices of the American Mathematical Society, vol. 77T-E51 (1977), pp. A--437.
[7] Jensen, R. B., and C. Karp, "Primitive recursive set functions", pp. 143--76 in Axiomatic Set Theory (Proceedings of the Symposia in Pure Mathematics, Vol. XIII, Part I, University of California, Los Angeles, 1967), American Mathematical Society, Providence, 1971.
[8] Kaye, R., and T. L. Wong, "On interpretations of arithmetic and set theory", Notre Dame Journal of Formal Logic, vol. 48 (2007), pp. 497--510.
[9] Kirby, L., "Addition and multiplication of sets", Mathematical Logic Quarterly, vol. 53 (2007), pp. 52--65.
[10] Kirby, L., "A hierarchy of hereditarily finite sets", Archive for Mathematical Logic, vol. 47 (2008), pp. 143--57.
[11] Lavine, S., "Finite mathematics", Synthese, vol. 103 (1995), pp. 389--420.
[12] Mahn, F.-K., "Zu den primitiv-rekursiven Funktionen über einem Bereich endlicher Mengen", Archiv für mathematische Logik und Grundlagenforschung, vol. 10 (1967), pp. 30--33.
[13] Montagna, F., and A. Mancini, "A minimal predicative set theory", Notre Dame Journal of Formal Logic, vol. 35 (1994), pp. 186--203.
[14] Paris, J. B., and L. A. S. Kirby, "$\Sigma \sbn$"-collection schemas in arithmetic", pp. 199--209 in Logic Colloquium '77 (Proceedings of the Conference, Wrocław, 1977), vol. 96 of Studies in Logic and the Foundations of Mathematics, North-Holland, Amsterdam, 1978.
Mathematical Reviews (MathSciNet):
MR519815
[15] Parsons, C., "On a number theoretic choice schema and its relation to induction", pp. 459--73 in Intuitionism and Proof Theory (Proceedings of the Conference, Buffalo, 1968), North-Holland, Amsterdam, 1970.
[16] Parsons, C., "On $n$"-quantifier induction, The Journal of Symbolic Logic, vol. 37 (1972), pp. 466--82.
[17] Previale, F., "Induction and foundation in the theory of hereditarily finite sets", Archive for Mathematical Logic, vol. 33 (1994), pp. 213--41.
[18] Rödding, D., "Primitiv-rekursive Funktionen über einem Bereich endlicher Mengen", Archiv für mathematische Logik und Grundlagenforschung, vol. 10 (1967), pp. 13--29.
[19] Świerczkowski, S., "Finite sets and Gödel's incompleteness theorems", Dissertationes Mathematicae (Rozprawy Matematyczne), vol. 422 (2003), p. 58.
[20] Tait, W. W., "Finitism", Journal of Philosophy, vol. 78 (1981), pp. 524--46.
[21] Tarski, A., "Sur les ensembles finis", Fundamenta Mathematicae, vol. 6 (1924), pp. 45--95.
[22] Tarski, A., The notion of rank in axiomatic set theory and some of its applications, edited by S. R. Givant and R. N. McKenzie, Contemporary Mathematicians. Birkhäuser Verlag, Basel, 1986. Originally published in Bulletin of the American Mathematical Society, vol. 61 (1955), Abstract 628, p. 443.
[23] Tarski, A., and S. Givant, A Formalization of Set Theory without Variables, vol. 41 of American Mathematical Society Colloquium Publications, American Mathematical Society, Providence, 1987.
Mathematical Reviews (MathSciNet):
MR920815
[24] von Neumann, J., "An axiomatization of set theory", pp. 393--413 in From Frege to Gödel. A Source Book in Mathematical Logic, 1879--1931, edited by J. van Heijenoort, Harvard University Press, Cambridge, 1967. Translation of ``Eine axiomatisierung der Mengenlehre,'' Journal für die reine und angewandte Mathematik, vol. 154 (1925), pp. 219--40.
[25] Wang, H., "Between number theory and set theory", Mathematische Annalen, vol. 126 (1953), pp. 385--409. Reprinted in Logic, Computers, and Sets, Chelsea Publishing Co., New York, 1970, pp. 478--506.
[26] Whitehead, A. N., and B. Russell, Principia Mathematica, 2d edition, Cambridge University Press, Cambridge, 1963.
[27] Zermelo, E., "Sur les ensembles finis et le principe de l'induction complète", Acta Mathematica, vol. 32 (1909), pp. 185--93.