Unformatted text preview: ms with function symbols by
equivalent, new predicates that have variables
2. Substitute for the EDB" global predicates
in terms of the views, but only where no
function symbols are introduced into the rules.
3 Justi ed because the views themselves
have no data with function symbols,
and other predicates have already had
all possible forms with function symbols
covered by other rules. Example Continued r1: r2:
r4 r6: Use manc1X; Y; Z for mancgX; Y ; Z .
3 No other variants of manc are needed in
this simple example.
Only r6 can be used for the m subgoal of
r1 r5 would introduce function symbols in
the head, and we already generated r8, an
appropriate variant of r1 where the m subgoal
has been uni ed with the pattern of the head
of r5 .
r1: mancX,Y :- v2 X,Y
No suitable replacement for the f subgoal
As for r1, it is necessary only to use r6 ,
r3: mancX,Y :- v2 X,Z & mancZ,Y
These inversion rules will be eliminated. r7: We must:
4 a Use r4 for the f subgoal, which requires
that A and X be uni ed because of...
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- Spring '09
- SEPTA Regional Rail, function symbols