Locally finite polynomial endomorphisms

We study polynomial endomorphisms F of C-N which are locally finite in the following sense: the vector space generated by r o F-n (n >= 0) is finite dimensional for each r epsilon C[ x 1, - - -, x(N)]. We show that such endomorphisms exhibit similar features to linear endomorphisms: they satisfy the Jacobian Conjecture, have vanishing polynomials, admit suitably defined minimal and characteristic polynomials, and the invertible ones admit a Dunford decomposition into "semisimple" and "unipotent" constituents. We also explain a relationship with linear recurrent sequences and derivations. Finally, we give particular attention to the special cases where F is nilpotent and where N = 2. (C) 2007 Elsevier B.V. All rights reserved.