Document Type : Research

Author

.

Abstract

Classical first-order logic is the most common logic in mathematics applications as well as in the study of logical foundations. From a long time ago, the only link between logic and mathematical topology was limited to the concept of type spaces, and there were no other links between these two domains. Recently, the basic links between these two branches (i.e. logic and topology) have been created, which have led to many applications in both areas of logic as well as in topology. In this article, we will study some of the most important links between these two branches of mathematics as well as their applications. One of the key concepts in mathematical logic and model theory is the concept of stability, which has a completely combinational statement. In this paper, we show that this concept is equivalent to a topological concept for a certain set of functions, and using this we prove a fundamental theorem of Shelah stability theory. We also describe the relationship between the concept of dependence and a topological property of a set of functions, and provide topological proofs of some of the important achievements of model theory. Some of the results of this paper are new.

Keywords

-         Ben-Yaacov I. (2014), Model theoretic stability and definability of types, after A. Grothendiek, Bulletin of Symbolic Logic, 20, pp 491-496.
-         Bourgain J., Fremlin D. H., and Talagrand M. (1978). Pointwise compact sets of baire-measurable functions. American Journal of Mathematics, 100(4): pp. 845-886.
-         Gaifman H. (1976), Models and types of Peano's arithmetic. Ann. Math. Logic, 9(3):223-306.
-         Grothendieck A. (1952), Crit`eres de compacit´e dans les espaces fonctionnels generaux, American Journal of Mathematics 74, 168-186.
-         Iovino I. (1999), Stable models and reexive Banach spaces. J. Symbolic Logic, 64(4):1595-1600.
-         Khanaki K. (2015), Stability, NIP, and NSOP; Model Theoretic Properties of Formulas via Topological Properties of Function Spaces, , Mathematical Logic Quarterly, submitted.
-         Khanaki K. and Pillay A. (2018), Remarks on NIP in a model, Mathematical Logic Quarterly, to appear.
-         Krivine, J.-L., and Maurey B. (1981), Espaces de Banach stables. Israel J. Math., 39(4):273-295.
-         Pillay A, (1982), Dimension theory and homogeneity for elementary extensions of a model, J. Symbolic Logic, vol 47, 147-160.
-         Pillay A. (2016), Generic stability and Grothendieck, South American Journal of Logic, Vol. 2, n. 2, p. 1-6.
-         Poizat B. (1981), Theories instables. J. Symbolic Logic, 46(3):513–522.
-         Shelah S. (1971), Stability, the f.c.p., and superstability; model theoretic properties of formulas in first order theory, Annals of Mathematical Logic, vol. 3, no. 3, pp. 271-362.
-         Simon P. (2015), Rosenthal compacta and NIP formulas, Fund. Math. vol. 231, 81-92.