W3C home > Mailing lists > Public > public-owl-wg@w3.org > December 2007

Re: racer documentation

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Wed, 12 Dec 2007 13:14:10 +0100 (CET)
To: Jeremy Carroll <jjc@hpl.hp.com>
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>, Ralf Moeller <r.f.moeller@tuhh.de>
Message-id: <Pine.LNX.4.64.0712101551060.3505@frege.inf.tu-dresden.de>

I guess the best solution is to ask Ralf, one of the two main people
behind Racer. I Cc: him this mail. Ralf, the question is what
datatypes and predicates Racer does offer. We found this in the Racer
manual:

--------------------------------------------------

RacerPro supports reasoning over natural numbers (N), integers (Z),
reals (R), complex numbers (C), and strings (S). For different sets,
different kinds of predicates are supported:

N | linear inequations with order constraints and integer coefficients
Z | interval constraints
R | linear inequations with order constraints and rational coefficients
S | equality and inequality

--------------------------------------------------

and this:

[[
if an attribute is declare to be of type real or integer it
is an error to use this attribute in terms for nonlinear polynoms. In
a similar way, currently, an attribute of type integer may not be used
in a term for a linear polynoms, either. If the coefficients are
integers, then cardinal (natural number, including 0) for the type of
attributes may be used in a linear polynom.
]]

The first snippet seems to indicate that Racer does not support 
multiplication of numbers, whereas the second talks about nonlinear
polynoms. Can you please clarify for us what Racer can do exactly?

Thanks for your support,

 	Carsten


On Mon, 10 Dec 2007, Jeremy Carroll wrote:
>
> Carsten Lutz wrote:
>> Another issue is that Racer indeed does not allow multiplication,
>
> That wasn't my reading ...
>
> [[
> if an attribute is declare to be of type real or integer it
> is an error to use this attribute in terms for nonlinear polynoms. In
> a similar way, currently, an attribute of type integer may not be used
> in a term for a linear polynoms, either. If the coefficients are
> integers, then cardinal (natural number, including 0) for the type of
> attributes may be used in a linear polynom.
> ]]
>
> seemed to be to say:
>
> non-linear polynomial => solve over complex numbers
> linear polynomial linear coefficients => solve over reals or over natural 
> numbers
>
> but no support for linear programming over the integers (as opposed to the 
> naturals)
>
> I don't have a copy of racer so can't experiment, but note that my reading is 
> at least a plausible reading.
>
> Jeremy
>
>

--
*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Wednesday, 12 December 2007 12:14:22 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:13:29 GMT