Submission date: 1 March 2017

Abstract:

We answer the following long-standing question of Kolchin: given a system of algebraic-differential equations S=0, in m derivatives and n variables over a differential field of characteristic zero, is there a computable bound, that only depends on the order of the system (and on the fixed data m and n), for the typical differential dimension of any prime component of S? We give a positive answer in a strong form; that is, we compute a (lower and upper) bound for all the coefficients of the Kolchin polynomial of every such prime component. We then show that, if we look at those components of a specified differential type, we can compute a significantly better bound for the typical differential dimension. This latter improvement comes from new combinatorial results on characteristic sets, in combination with the classical theorems of Macaulay and Gotzmann on the growth of Hilbert-Samuel functions.

Mathematics Subject Classification: 12H05, 14Q20

Keywords and phrases: Kolchin polynomial, typical differential dimension, Hilbert-Samuel functions

Full text arXiv 1703.00509: pdf, ps.