Pat Hayes wrote:
At 6:31 PM -0400 6/26/08, Ogbuji, Chimezie wrote:
Hey, Pat. Comments below
> I would disagree about this case being the exception.
>Negation as failure can be validly used to infer from a
>failure if the data is controlled (which is especially the
>case with
Adrian and Toby,
Some comments:
TC> Date had it right. NULL is neither true nor false.
Yes, and he made some recommendations that can be applied to
any logic-based notation. One of them is to introduce special
constants or relations to handle various kinds of nonmonotonic
issues, and then wr
Pat, John, Chimeze and all --
Illuminating discussion.
Two points:
1. If you move to from SQL-like NAF reasoning, to full FOL with closure
statements at the meta level, you may also be moving from low order
polynomial computational complexity to exponential, or even into the
undecidable region.
Folks,
I'd just like to summarize a few points, which reinforce the claim I
made earlier: There is an open-ended number of different variations of
nonmonotonic logic, and it's impossible to adopt a one-size-fits-all
solution for nonmonotonic logic.
To paraphrase Tolstoy, every happy logic (i.e
At 10:35 PM -0400 6/26/08, Bob Futrelle wrote:
If I have a database of *all* employees in a company and a query for a
person returns nothing, then that failure allows me to assert that
that person is not an employee.
As long as you know that the database has that all-encompassing
quality, yes.
If I have a database of *all* employees in a company and a query for a
person returns nothing, then that failure allows me to assert that
that person is not an employee. It's a matter of deciding what your
universe of discourse is, is it not?
- Bob Futrelle
At 6:31 PM -0400 6/26/08, Ogbuji, Chimezie wrote:
Hey, Pat. Comments below
> I would disagree about this case being the exception.
Negation as failure can be validly used to infer from a
failure if the data is controlled (which is especially the
case with well-designed experiments where it w
Hey, Pat. Comments below
> I would disagree about this case being the exception.
>Negation as failure can be validly used to infer from a
>failure if the data is controlled (which is especially the
>case with well-designed experiments where it would be
>irresponsible to to do
