[isabelle-dev] HOL Importer failure

Florian Haftmann florian.haftmann at informatik.tu-muenchen.de
Wed Oct 22 19:24:02 CEST 2014


Proof failed.
1. even (id 0) = True & (ALL n. even (Suc n) = odd n)
The error(s) above occurred for the goal statement (line 12 of
EX x. x : {x. integer x}
At command "import_file" (line 12 of

I am currently at a loss to explain what's happening here.

The immediate cause is the abolishment of »even« as logical constant.

I have tried funny things like

> definition even :: "nat ⇒ bool"
> where
>   "even = Parity.even"
> lemma EVEN [import_const "EVEN" : even]:
>   "even (id 0∷nat) ⟷ True ∧ (∀n. even (Suc n) ⟷ ¬ even n)"
>   by (simp add: even_def)

but the result does not change.

What seems especially strange to me is that the statement to prove does
not contain reals at all.

Any suggestions?

Thanks a lot,


PGP available:

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