src/HOL/Algebra/abstract/Factor.thy

A new implementation for presburger arithmetic following the one suggested in technical report Chaieb Amine and Tobias Nipkow. It is generic an smaller.
the tactic has also changed and allows the abstaction over fuction occurences whose type is nat or int.

(*
    Factorisation within a factorial domain
    $Id$
    Author: Clemens Ballarin, started 25 November 1997
*)

Factor = Ring +

consts
  Factorisation	:: ['a::ring, 'a list, 'a] => bool
  (* factorisation of x into a list of irred factors and a unit u *)

defs
  Factorisation_def	"Factorisation x factors u == 
                           x = foldr op* factors u &
                           (ALL a : set factors. irred a) & u dvd 1"

end