--- layout: fc_discuss_archives title: Message 16 from Frama-C-discuss on January 2016 ---
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[Frama-c-discuss] What is the point of ``All models'' in Alt-Ergo?



By default, to prove a goal from a set of hypotheses, Alt-Ergo negates
the goal and attempts to establish unsatisfiability.

With the experimental and undocument options related to "models", the
goal is not negated anymore, hence the wrong results you get. They are
not supposed to be used from Frama-C or Why3.

Curiosity is of course good for research, but remember that sometimes
experiments can produce a "boom".

- Claude




Le 27/01/2016 04:36, Wolfram Kahl a écrit :
> Since I cannot find Alt-Ergo documentation nor mailing list,
> I ask this question here, since I am using it only from Frama-C:
> What is the point of the ``All models'' option in Alt-Ergo?
> With that enabled (I am using it via the GUI as started from
> WP-goals in Frama-C), it has no trouble to decide
> 
>   //@ lemma falsum: 0 == 1;
> 
> as ``Valid (0.01s)''.
> 
> (Without that option, it only says ``I don't know (sat) (0.01s)'',
> which I still consider as a rather weak answer...)
> 
> The closest I found to documentation is the help flag:
> 
>   alt-ergo -h
> 
> produces
> 
>   -all-models experimental support for all models
>   -model experimental support for models on labeled terms
>   -complete-model experimental support for complete model
> 
> , but I don't quite know how I am supposed to understand these ---
> is validity of falsum a result of the experimental nature of these,
> or is it by design of ``all models''?
> 
>  $ alt-ergo -version
> 0.99.1
> 
> 
> Wolfram
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> 

-- 
Claude Marché                          | tel: +33 1 69 15 66 08
INRIA Saclay - ÃŽle-de-France           |
Université Paris-sud, Bat. 650         | http://www.lri.fr/~marche/
F-91405 ORSAY Cedex                    |