Negation as failure. II. (English) Zbl 0603.68094

Shepherdson, John C.

J. Logic Program. 2, 185-202 (1985).

[For Part I see ibid. 1, 51-79 (1984; Zbl 0575.68094).]
It is questioned whether there is any simple and useful logical meaning of negation as failure in the general case. Special kinds of databases are studied where the relationship of the completed database to negation as failure is closer, e.g., where the database is definite Horn or hierarchic. The discussion suggests that intuitionistic logic is more appropriate than classical logic, but leaves still doubtful whether there is any useful logical characterization of negation as failure.

Reviewer: E.Knuth

MSC:

68T15	Theorem proving (deduction, resolution, etc.) (MSC2010)
68P20	Information storage and retrieval of data
68N01	General topics in the theory of software

Keywords:

logic programming; closed world assumption; completed database; intuitionistic logic; classical logic

Citations:

Zbl 0575.68094