matita/matita/contribs/lambdadelta/ground_2/xoa/ex_4_1_props.ma

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  14
  15 include "ground_2/xoa/xoa.ma".
  16
  17 (* Properties with multiple existental quantifier (5, 1) ********************)
  18
  19 lemma ex4_commute (A0) (P0,P1,P2,P3:A0→Prop):
  20                   (∃∃x0. P0 x0 & P1 x0 & P2 x0 & P3 x0) → ∃∃x0. P2 x0 & P3 x0 & P0 x0 & P1 x0.
  21 #A0 #P0 #P1 #P2 #P3 * /2 width=5 by ex4_intro/
  22 qed-.