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(************** beyond this point the words Axiom, Parameter, ***)
(**************   Declare don't occur  **************************)
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(************* Existence  *******************)
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Variable P : Ens -> Prop.
Variable X : Ens.
Hypothesis p : P X.
Hypothesis h : DOESNT_EXIST P.
Let step1 : ~ P X.
Proof h X.

Lemma EXISTS_th1_proof_Out : False.
Proof step1 p.