Re: play(player, game)

>>>>> Octav Popescu <[email protected]> writes:

> Then I guess my question is again: Any idea when you'll issue the next 
> release? :-)

We are working on another release which will be licensed open-source
similar to STELLA.  It will also include our database interface for
PowerLoom (currently only supporting MySQL).

> Another question: irrespective of the CLOSED declaration, does PowerLoom do 
> 3-value (or 5-value with the defaults) logic computation? Like saying (AND 
> UNKNOWN FALSE) = FALSE, (AND UNKNOWN TRUE) = UNKNOWN, (OR UNKNOWN TRUE) = 
> TRUE, (OR UNKNOWN FALSE) = UNKNOWN.

Yes, for example:

STELLA(3): (defrelation happy (?x))
|r|HAPPY
STELLA(4): (assert (not (happy joe)))
|P|(NOT (HAPPY JOE))
STELLA(5): (ask (happy fred))
UNKNOWN
STELLA(6): (ask (and (happy joe) (happy fred)))
FALSE
STELLA(7): (ask (or (happy joe) (happy fred)))
UNKNOWN
STELLA(8): (ask (or (not (happy joe)) (happy fred)))
TRUE
STELLA(10): (ask (and (not (happy joe)) (happy fred)))
UNKNOWN
STELLA(11): 

Hans

> --On Tuesday, May 24, 2005 6:46 PM -0700 Hans Chalupsky <[email protected]> wrote:

>> Octav,
>> 
>> you are right that the primary reason for this is the asymmetric
>> effort by PowerLoom on proving the query as stated as opposed to
>> trying to prove its negation.  You are also right that the system
>> looks somewhat stupid/buggy using this behavior when querying closed
>> relations.  Tom Russ was offended by this also recently and has been
>> working on a fix.  I'm not sure exactly where we are on this, but
>> we'll try to fix this for the next release.
>> 
>> Hans
>> 
>>>>>>> Octav Popescu <[email protected]> writes:
>> 
>>> Hans,
>>> After looking a little into this, now I'm confused too about the semantics
>>> of  the CLOSED predicate. :-) I understand why the example below does not
>>> lead to  any contradictions. But I'm not sure I understand why CLOSED only
>>> has effect  on NOT questions. Like for instance:
>> 
>>> ? (defconcept player)
>>> | c|PLAYER
>>> ? (assert (closed player))
>>> | P|(CLOSED PLAYER)
>>> ? (assert (player jano))
>>> | P|(PLAYER JANO)
>>> ? (ask (not (player chess)))
>>> Processing check-types agenda...
>>> TRUE
>>> ? (ask (player chess))
>>> UNKNOWN
>> 
>>> I'm not sure I understand why the last query doesn't return FALSE. I take
>>> it  it has to do with the fact that PowerLoom doesn't put much effort into
>>> disproving a query. The manual says:
>> 
>>> "The PowerLoom command ask returns one of three values: true if it can
>>> prove  the truth of a proposition, false if it can easily prove the
>>> falsity of a  proposition and otherwise it returns unknown."
>> 
>>> So in this case PowerLoom does know that the query failed, and it seems to
>>> me  it would be easy to check that the predicate is CLOSED, and then
>>> change the  result to FALSE. This would be more in line with the "negation
>>> as failure"  mode. Is there a problem with this?
>> 
>>> Thanks,
>>> Octav
>> 
>>> --On Friday, May 13, 2005 13:11 -0700 Hans Chalupsky <[email protected]> wrote:
>> 
>>>> Krzysztof,
>>>> 
>>>> I'm not sure why you think the last assertion should not be possible.
>>>> At that point both JANO and CHESS are of type PLAYER (via explicit
>>>> assertion) and GAME (inferred via the type constraint on PLAY).  You
>>>> asserted GAME and PLAYER to be closed which only means (NOT (GAME/PLAYER
>>>> ?x))  will be concluded if (GAME/PLAYER ?x) cannot be inferred.  So, there
>>>> are no contradictions I can see.
>>>> 
>>>> Hans
>>>> 
>>>>>>>>> Krzysztof Janowicz <[email protected]> writes:
>>>> 
>>>>> hi,
>>>>> i do not understand why the last assert is possible, can anyone give me
>>>>> a hand? can i assert everything independent of the definitions made
>>>>> bevor?
>>>> 
>>>>> thanks!
>>>> 
>>>>> (DEFCONCEPT PLAYER)
>>>>> (DEFCONCEPT GAME)
>>>>> (DEFRELATION PLAY (?X ?Y)
>>>>> :=> (AND (PLAYER ?X) (GAME ?Y)))
>>>> 
>>>>> // or (defrelation play ((?x player) (?y game)))
>>>> 
>>>>> (ASSERT (CLOSED GAME))
>>>>> (ASSERT (CLOSED PLAYER))
>>>>> (ASSERT (PLAYER JANO))
>>>>> (ASSERT (PLAYER CHESS))
>>>>> (ASSERT (PLAY JANO CHESS))
>>>>> (ASSERT (PLAY JANO JANO))
>>>> 
>>>> 
>>>>> regards
>>>>> k.janowicz
>>>>> _______________________________________________
>>>>> powerloom-forum mailing list
>>>>> [email protected]
>>>>> http://mailman.isi.edu/mailman/listinfo/powerloom-forum
>>>> 
>>>> _______________________________________________
>>>> powerloom-forum mailing list
>>>> [email protected]
>>>> http://mailman.isi.edu/mailman/listinfo/powerloom-forum
>>>> 
>> 
>>