Re: strange behavior of subset

Ok I found the problem :

subset is based on membercheck that succeeds only once.

Bye.
Dominique


Le 07/01/2014 14:17, db a écrit :
> Hello,
>
> I used swi prolog Multi-threaded, 64 bits, Version 7.1.4
> under Ubuntu.
>
> I am suprise by the behavior of the subset predicate :
>
>
> ?- subset([p(A), q(A,B)], [p(1), p(2), q(2,3)]).
> false.
>
>
> ?- subset([p(A), q(A,B)], [p(2), p(1), q(2,3)]).
> A = 2,
> B = 3.
>
> Thus subset takes into account the order of the element
> in the sets, what is not expected when one deals with sets.
>   Is is normal ?
>
> Thanks a lot
>
> Dominique
>
>
>
> _______________________________________________
> SWI-Prolog mailing list
> [email protected]
> https://lists.iai.uni-bonn.de/mailman/listinfo.cgi/swi-prolog
>
> !DSPAM:152,52cbff64251284767677671!
>