CNF_Horn 5 - ), ( ( )) ( ( )) ( ( ( ) ( )( ( ))) , ( ) , (...

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Skolems Skolems are used to get rid of existential quantifiers: Skolem constants: When NOT in scope of another quantifier Skolem functions: When in scope of another quantifier York University- CSE 3401 21 ) 1 , ( ) 1 ( )) , ( ) ( ) (( g eve mother g female X eve mother X female X ) ), ( 2 ( ) ( ) ( ) , ( ) ( ) )( ( X X g mother X human X X Y mother X human Y X 02-CNF & Horn
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Another example 1. Remove imp. and equiv. 2. Move negations inwards 3. Rename variables 4. Move quantifiers to front 5. Skolemize 6. Distribute OR over AND 7. Remove quantifiers York University- CSE 3401 22             ). , ( : ) ), ( ( ) ), ( ( ) , ( ) ), ( ( ) , ( ) )( ( ) , ( ) , ( ) )( )( ( ) , ( ) ( ) , ( ) ( ) ( ) , ( ) ( ) , ( ) ( ) ( ) , ( ) ( ) , ( ) ( ) ( ) , ( ) ( ) , ( ) ( ) ( Y X m X X g p X X g p Y X m X X g p Y X m Y X X Z p Y X m Z Y X X Z p Z Y X m Y X X Y p Y Y X m Y X X Y p Y Y X m Y X X Y p Y Y X m Y X 02-CNF & Horn
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Example All Martians like to eat some kind of spiced food. [ from Advanced Prolog Techniques and examples- Peter Ross ] York University- CSE 3401 23 ))) ( , ( ) ( ( ))) ( ), ( ( ) ( ( ))) ( ( ) ( ( ))) ( ( ) ( ( )))) ( , ( ) ( ( ))) ( ), ( ( ) ( ( ))) ( ( ) ( ( ))) ( ( ) ( )(( ( )))) ( , ( )) (
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Unformatted text preview: ), ( ( )) ( ( )) ( ( ( ) ( )( ( ))) , ( ) , ( ) ( ) ( ( ) ( )( )( )( ( ))) , ( ) , ( ) ( ) ( )( )( ( ) ( )( ( ))) , ( ) , ( ) ( ) ( )( )( ( ) ( )( ( X f X likes X martian X s X f contains X martian X s spice X martian X f food X martian X f X likes X martian X s X f contains X martian X s spice X martian X f food X martian X X f X likes X s X f contains X s spice X f food X martian X Y X likes Z Y contains Z spice Y food X martian Z Y X Y X likes Z Y contains Z spice Y food Z Y X martian X Y X likes Z Y contains Z spice Y food Z Y X martian X 02-CNF & Horn...
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This note was uploaded on 02/14/2012 for the course CSE 3401 taught by Professor Movahedi during the Fall '11 term at York University.

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CNF_Horn 5 - ), ( ( )) ( ( )) ( ( ( ) ( )( ( ))) , ( ) , (...

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