Re: Syntax question

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Thanks Thomas,

Based on your response I could probably infer what the following mean as
well.  However, perhaps you could provide a brief synopsis for precision and
clarity.

:<=
:=>
:<<=
:<=>
:<=>>
:<<=>
:<<=>>

Thanks much,
Cameron.


On Wed, Mar 3, 2010 at 2:15 PM, Thomas Russ <[email protected]> wrote:

>
> On Mar 3, 2010, at 9:51 AM, Cameron Ross wrote:
>
>  Hi,
>>
>> Its not readily apparent from the PowerLoom documentation how to interpret
>> :=>>.  Enlightenment would be very much appreciated.
>>
>
> The extra > on the arrow heads are used for inference direction control.
>
> Normally, with a rule like
>
>   (A ?x)  :=> (B ?x)
>
> PowerLoom is free to run this rule either in a forward direction or a
> backward direction.  Running it forward means that if we assert (A i-1) then
> we immediately conclude (B i-1).  Running backward means that if we are
> trying to prove (B i-1) or find (B ?x) then we look to see if (A i-1) is
> already known.
>
> When extra arrow heads are used, this tells PowerLoom the desired direction
> of the rule, so that
>
>  (A ?x)  :=>>  (B ?x)
>
> will be run only in the forward direction.  This gives some additional
> inference control and affects both what will be inferred as well as the
> performance of the reasoner.
>
>
>


-- 
Cameron Ross
Kojeware Corporation
705-929-1492

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Thanks Thomas,<div><br></div><div><div>Based on your response I could proba=
bly infer what the following mean as well. =A0However, perhaps you could pr=
ovide a brief synopsis for precision and clarity.</div><div><br></div><div>
:&lt;=3D</div><div>:=3D&gt;</div><div>:&lt;&lt;=3D</div><div>:&lt;=3D&gt;</=
div><div>:&lt;=3D&gt;&gt;</div><div>:&lt;&lt;=3D&gt;</div><div>:&lt;&lt;=3D=
&gt;&gt;</div><div><br></div><div>Thanks much,</div><div>Cameron.</div><div=
><br></div>
<div><br><div class=3D"gmail_quote">On Wed, Mar 3, 2010 at 2:15 PM, Thomas =
Russ <span dir=3D"ltr">&lt;<a href=3D"mailto:[email protected]">[email protected]</a>&g=
t;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0=
 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class=3D"im"><br>
On Mar 3, 2010, at 9:51 AM, Cameron Ross wrote:<br>
<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
Hi,<br>
<br>
Its not readily apparent from the PowerLoom documentation how to interpret =
:=3D&gt;&gt;. =A0Enlightenment would be very much appreciated.<br>
</blockquote>
<br></div>
The extra &gt; on the arrow heads are used for inference direction control.=
<br>
<br>
Normally, with a rule like<br>
<br>
 =A0 (A ?x) =A0:=3D&gt; (B ?x)<br>
<br>
PowerLoom is free to run this rule either in a forward direction or a backw=
ard direction. =A0Running it forward means that if we assert (A i-1) then w=
e immediately conclude (B i-1). =A0Running backward means that if we are tr=
ying to prove (B i-1) or find (B ?x) then we look to see if (A i-1) is alre=
ady known.<br>

<br>
When extra arrow heads are used, this tells PowerLoom the desired direction=
 of the rule, so that<br>
<br>
 =A0(A ?x) =A0:=3D&gt;&gt; =A0(B ?x)<br>
<br>
will be run only in the forward direction. =A0This gives some additional in=
ference control and affects both what will be inferred as well as the perfo=
rmance of the reasoner.<br>
<br>
<br>
</blockquote></div><br><br clear=3D"all"><br>-- <br>Cameron Ross<br>Kojewar=
e Corporation<br>705-929-1492<br>
</div></div>

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