Re: example with 2 combined searches: does "No solution" guarantee no solution actually?

From: Michael Hanus <mh_at_informatik.uni-kiel.de>
Date: Wed, 20 Apr 2011 01:32:13 +0200

Ivan Zakharyaschev wrote:
> Do you have perhaps an answer to the question whether the intuition
> that I felt was broken in this case is actually true given the
> specification of the Curry language:
>
> that if a correct Curry implementation prints "No solution", then it
> is actually so that no solution can be invented (by "solution" I guess
> one could mean without going into formalities a result and assignments
> to free variables such that
> they conform to all the imposed constraints)?

This is correct. "No solution" means that there does not exist a
solution to this problem (provided that the program does not use
unsafe non-declarative features that are provided by some
implementations). Beyond a solution and no solution there
could also be the case that a computation suspends or does not terminate
which means that one has no definite information about the solvability
of the problem.

Best regards,

Michael
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Received on Wed Apr 20 2011 - 02:07:56 CEST

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