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Topic: PROLOG does SO have NOT() !!
Replies: 3   Last Post: Nov 20, 2012 3:33 PM

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Graham Cooper

Posts: 4,358
Registered: 5/20/10
PROLOG does SO have NOT() !!
Posted: Nov 20, 2012 3:39 AM
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Exactly the same way we use not().

Failure to return a result can be programmed for ANY PREDICATE


e.g. Boolean Predicates

if(X,Y) :- true(X) , true(Y)
if(X,Y) :- not(X) , true(Y)
if(X,Y) :- not(X) , not(Y)
not(if(X,Y)) :- true(X) , not(Y)


A predicate with more than 2 values!

gender(m). 1
gender(f). 2
not(gender(X)). 3

Prolog searches for a match from top to bottom,
it will return
--> gender(m)

--> not(gender(t)).

for any value other than m or f!

You can PROGRAM the predicate NOT(...)

for any predicate with a FINITE SET OF ARGUMENT VALUES!


if( if(t(S),f(R)) , if(t(R),f(S)) ).
if it's sunny then it's not raining
if it's raining then it's not sunny

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