Exercise-ch2: Difference between revisions

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== Formulae ==
== Formulae ==


∀ ∃ ∧ ∨ ⊂ ⊃ ¬
<!-- &forall; &exist; &and; &or; &sub; &sup; &not; -->


For the following exercises we use names and properties from the ''The Lord of the Rings'' novels.
For the following exercises we use names and properties from the ''The Lord of the Rings'' novels.
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+ '''gandalf'''
+ '''gandalf'''
+ '''hobbit'''
+ '''hobbit'''
- &exist; ''x''
- &exist;''x''
|| A quantifier, &forall; or &exist;, can only be used with a variable and a formula. For example: &exist;''x''('''hobbit'''(''x''))
|| A quantifier, &forall; or &exist;, can only be used with a variable and a formula. For example: &exist;''x''('''hobbit'''(''x''))
- '''know'''('''gandalf''')
- '''know'''('''gandalf''')
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- '''frodo''' &and; '''gandalf'''
- '''frodo''' &and; '''gandalf'''
+ &forall;''x'' ('''hobbit'''(''x'') &sup; x = '''gandalf''')
+ &forall;''x'' ('''hobbit'''(''x'') &sup; x = '''gandalf''')
+ &exist;''y''('''hobbit'''(''x'') &or; '''wizard'''(''gandalf''))
|| Note: The variable bound by the quantifier, ''y'', need not occur in the scope of the quantifier.


</quiz>
</quiz>

Revision as of 19:44, 15 March 2013

Additional Exercises for Chapter 2: Predicate Logic

Formulae

For the following exercises we use names and properties from the The Lord of the Rings novels.

Names: frodo, sam, gandalf, aragorn
1-place predicates: hobbit
2-place predicates: know, help

  

1 Click on the items that are well-formed expressions of the semantic representation language.

gandalf
hobbit
x
know(gandalf)

2 Click on the expressions that are well-formed formulae.

hobbit
frodo
hobbit(aragorn)
frodogandalf
x (hobbit(x) ⊃ x = gandalf)
y(hobbit(x) ∨ wizard(gandalf))