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(* 02110-1301 USA                                                     *)
(** lemmas. Some nice lemmas, mostly about le, lt, and mult.  @author Olga Caprotti and Martijn Oostdijk @version $Revision$ *)
Global Set Asymmetric Patterns.

Lemma Zmult_ab0a0b0 : forall a b : Z, (a * b)%Z = 0%Z -> a = 0%Z \/ b = 0%Z.