prolog,universal,existential-type,quantifiers , universal and existential quantifier in prolog

## Question:

Tag: prolog,universal,existential-type,quantifiers

How can I implement following rules in prolog.

I write the “ No spiders are mammals” sentence as Existential and universal:

``````¬∃x(mammals(X) ∧ spider(X) ) //It is not the case that mammals are spider

∀X(mammals(X) ⇒ ¬spider(X)) //All mammals are non-spider.
``````

Suppose you have a database with the following facts:

``````mammals(cat).
mammals(dog).
...

spider(blackwidow).
...
``````

Now you can issue a rewrite your sentence into a prolog query quite straightforward:

¬∃x(mammals(X) ∧ spider(X) ) //It is not the case that mammals are spider

``````?- \+((mammals(X), spider(X))).
true.
``````

and

∀X(mammals(X) ⇒ ¬spider(X)) //All mammals are non-spider.

``````?- forall(mammals(X), \+spider(X)).
true.
``````

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