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Re: [Coq-Club] forall implication


Chronological Thread 
  • From: richard dapoigny <richard.dapoigny AT univ-savoie.fr>
  • To: coq-club AT inria.fr
  • Subject: Re: [Coq-Club] forall implication
  • Date: Mon, 27 Apr 2015 17:11:25 +0200
  • Organization: LISTIC

Le 27/04/2015 16:51, Pierre Courtieu a écrit :
If I understand well you want to prove:

x : A
Hi : P x
======
forall y, P y

which is false.

Maybe you should try to prove something else :)
Ok, I do. Thanks.

Best regards,
P.




2015-04-27 16:17 GMT+02:00 richard dapoigny
<richard.dapoigny AT univ-savoie.fr>:
Le 27/04/2015 15:57, Pierre Courtieu a écrit :
Hi,

This is no true and therefore not provable.

But if you add parenthesis over the first quantified part then it is a
different property (and probably the on one you meant?) that is
provable by "intro h; assumption."

(forall x, (* some complex function depending on x*)) -> forall y, (*
the same complex function depending on y*)

For examepl:

Variable A:Type.
Variable P: Type -> Prop.

Goal (forall x, (P x)) -> (forall y, P y).
Proof.
intro h.
assumption.

Best regards,
Pierre
Thanks for the prompt answer!
Yes I would like to have the goal you suggest but the problem is that the
left part is generated by applying generalize x Hi (wher Hi is another
hypothesis) and therefore I cannot obtain the whole expression due to a lack
of parentheses


2015-04-27 15:42 GMT+02:00 richard dapoigny
<richard.dapoigny AT univ-savoie.fr>:
Hi all,
I try to demonstrate a goal having the form:
forall x, (* some complex function depending on x*) -> forall y, (* the
same
complex function depending on y*)
Is there a simple way to do it?
Thanks in advance,
Richard





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