Re: multiset ordering

Dear Pierpaolo,

Thankyou for your quick reply.

What should the goal gt_ms_onestep([3],X) bind X to? What does happen instead?

How many and what kind of solutions has the goal permutation(X,Y) ?

Do you think that the goal 3 > T will generate good values for T?
(it doesn't, it generates the error you get, instead).

I see that my code behaves quite different from what I expected.
I thought that every predicate I wrote was invertible in
every parameter, but as you pointed out this is not the case.

Is there a way to write predicates such that every variable
can be uninstantiated when you submit a query to Prolog?
I don't know, some design-rule to follow...

Anyway, I'm reading the book "Programming in Prolog" by
Clocksin and Mellish,
http://www.amazon.co.uk/exec/obidos/ASIN/3540583505/bindingtimeli-21
and I hope that at the end of my reading I will have more clear ideas.

Ciao,
GG

.

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