Skip to Main Content
Foundations of Deductive Databases and Logic Programming
book

Foundations of Deductive Databases and Logic Programming

by Jack Minker
May 2014
Intermediate to advanced content levelIntermediate to advanced
752 pages
35h 3m
English
Morgan Kaufmann
Content preview from Foundations of Deductive Databases and Logic Programming
164
Van
Gelder
and the facts about b and g:
M
1,2) £(2,3)
*(2,1) £(3,2)
M3,4)
*(4,3)
By considering only tight NF-trees, the looping problem disappears, and
atoms like p(l,3) and p(2,3) can be put into FS
4
. For example, p(l,3) can
reduce to b(l,2) andp(2,3), but thenp(2,3) cannot reduce to b(2,l) andp(l,3)
because tightness is violated. The tight tree semantics with this program will
therefore compute the more expected result that SS also includes
{e(2,3),
e(3,2), a(2,2), a(2,3), a(3,2), a(3,3)}.
EXAMPLE 6
Recall that P
4
in Example 4 is the program with rules
p(X)^a(X),
c(X).
p(X)^
^a(X),d(X).
a(X)+b(X).
b(X)*-a(X).
together with the facts
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Concepts and Semantics of Programming Languages 1

Concepts and Semantics of Programming Languages 1

Therese Hardin, Mathieu Jaume, Francois Pessaux, Veronique Viguie Donzeau-Gouge
Handbook of Constraint Programming

Handbook of Constraint Programming

Francesca Rossi, Peter van Beek, Toby Walsh

Publisher Resources

ISBN: 9781483221120