Abstract
This is the first of two papers devoted to the proof of Zilber’s dichotomy for the case of difference-differential fields of characteristic zero. In this paper we use the techniques exposed in [9] to prove a weaker version of the dichotomy, more precisely, we prove the following: in DCFA the canonical base of a finite-dimensional type is internal to the fixed field of the field of constants. This will imply a weak version of Zilber’s dichotomy: a finite-dimensional type of SU -rank 1 is either 1-based or non-orthogonal to the fixed field of the field of constants.
References
Bustamante Medina, R.F. (2007) “Differentially closed fields of characteristic zero with a generic automorphism”, Revista de Matemática: Teoría y Aplicaciones 14(1): 81–100.
Bustamante Medina, R.F. (2008) “Rank and dimension in difference-differential fields”, Submitted.
Chatzidakis, Z.; Hrushovski, E. (1999) “Model theory of difference fields”, Transactions of the American Mathematical Society 351(8): 2997–3071.
Eisenbud, D. (1995) Commutative Algebra. Springer-Verlag, New York.
Marker, D.; Messmer, M.; Pillay, A. (1996) Model Theory of Fields, volume 5 of Lecture Notes in Logic. Springer-Verlag, Berlin.
Marker, D. (2000) “Model theory of differential fields”, in: D. Haskell, A. Pillay & C. Steinhorn (Eds.) Model Theory, Algebra, and Geometry, volume 39 of Math. Sci. Res. Inst. Publ., Cambridge Univ. Press, Cambridge: 53–63.
Pierce, D.; Pillay, A. (1998) “A note on the axioms for differentially closed fields of characteristic zero”, J. Algebra 204(1): 108–115.
Pillay, A. (2002) “Model-theoretic consequences of a theorem of Campana and Fujiki”, Fundamenta Mathematicae 174(2): 187–192.
Pillay, A.; Ziegler, M. (2003) “Jet spaces of varieties over differential and difference fields”, Selecta Mathematica. New Series 9(4): 579–599.
Shafarevich, I.R. (1977) Basic Algebraic Geometry. Springer-Verlag, Berlin