- From: Francois Bry <bry@ifi.lmu.de>
- Date: Mon, 08 May 2006 10:02:41 +0200
- To: public-rif-wg@w3.org
Michael Kifer wrote:
>> Michael Kifer wrote:
>>
>>>> Do you really mean this, i.e., that there is essentially only one domain of
>>>> discourse? Are there no possibilities of non-trivial identity, for example
>>>> between f(a) and f(b)?
>>>>
>>>>
>>> With equality the domain of interpretation is a set of equivalence classes
>>> over the Herbrand universe. Herbrand universe != Herbrand domain in case
>>> there is equality. This is all standard stuff in Logic Programming.
>>> http://citeseer.ist.psu.edu/context/6262/0
>>> Also see the classical Chang & Lee's book:
>>>
>>> @book{ chang-lee,
>>> author = "C.L. Chang and R.C.T. Lee",
>>> title = "Symbolic Logic and Mechanical Theorem Proving",
>>> publisher = "Academic Press",
>>> year = 1973
>>> }
>>>
>>>
>>>
>> To the beat of my understanding, things can be a little bit more
>> differentiated.
>>
>> There are two approaches to equality in logic programmi9ng and rule
>> languages.
>>
>> - the simple and limited treatment of equality as "syntactical
>> equality". In this case, f(a) != f(b) and the (in)equality between
>> expressions containing variables is only allowed if these variables are
>> bound when this expression is evaluated.
>>
>
> This like "no equality".
In a way, this is right. But Prolog very weak treatment of equality is
- very usefull in practice
- widespread among rule languages.
François
Received on Monday, 8 May 2006 08:02:57 UTC