(* Properties of abstract class field $Id: Field.thy,v 1.3 2005/09/17 18:49:14 wenzelm Exp $ Author: Clemens Ballarin, started 15 November 1997 *) theory Field imports Factor PID begin instance field < "domain" apply intro_classes apply (rule field_one_not_zero) apply (erule field_integral) done instance field < factorial apply intro_classes apply (rule TrueI) apply (erule field_fact_prime) done end