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[Coq-Club] @eq Type -> @eq Set


Chronological Thread 
  • From: Jason Gross <jasongross9 AT gmail.com>
  • To: coq-club AT inria.fr
  • Subject: [Coq-Club] @eq Type -> @eq Set
  • Date: Tue, 26 Jun 2012 23:49:09 -0400

I'm trying to prove the following lemma, and getting an error on [Qed].

Lemma eqType2Set (a b : Set) : @eq Type a b -> @eq Set a b.
  intro; subst; reflexivity.
Qed.

Coq says

Error: Illegal application (Type Error): 
The term "eq" of type "forall A : Type, A -> A -> Prop"
cannot be applied to the terms
 "Set" : "Type"
 "a0" : "Type"
 "b" : "Set"
The 2nd term has type "Type" which should be coercible to 
"Set".

If I [Set Printing All] and [Show Proof], Coq tells me that the proof is 
(fun (a b : Set) (H : @eq Type a b) =>
 @eq_ind_r Type b (fun a0 : Type => @eq Set a0 b) (@eq_refl Set b) a H)


Does anyone have ideas/suggestions for how to make this proof go through?  Does it need an axiom?

-Jason



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