Lecture-10

# Lecture-10 - Artificial Intelligence CS 165A 165A Thursday...

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Artificial Intelligence S 165A CS 165A Thursday, Feb 03, 2011 irst order logic (Ch 8) First order logic (Ch. 8) Inference (Ch. 9) 1

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Notes • HW#3 due next Tuesday idterm next Thursday Midterm next Thursday 2
Simple example of inference in FOL Bob is a buffalo Pat is a pig Buffalo(Bob) Pig(Pat) KB 0 Buffaloes outrun pigs Buffalo( x ) Pig( y ) Outrun( x,y ) Does Bob outrun Pat? KB entails Outrun(Bob, Pat)? KB 0 S KB 0 |– Buffalo(Bob) Pig(Pat) (And-Introduction) KB 1 KB 1 |– Buffalo(Bob) Pig(Pat) Outrun(Bob, Pat) (Universal Instantiation) [coming soon] B utrun(Bob, Pat) KB 2 3 KB 2 | Outrun(Bob, Pat) (Modus Ponens) KB 3

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Using FOL to express knowledge • One can express the knowledge of a particular domain in first-order logic • Example: The “kinship domain” Objects: people roperties: ender family relationships Properties: gender, family relationships Unary predicates: Male, Female, MotherOf, FatherOf Binary predicates: Parent, Sibling, Brother, Sister, Son, aughter, Father, Mother, Uncle, Aunt, Grandparent, Grandfather, Daughter, Father, Mother, Uncle, Aunt, Grandparent, Grandfather, Grandmother, Husband, Wife, Spouse, Brother-in-law, Stepmother, etc…. Functions: MotherOf, FatherOf… • Note: There is usually (always?) more than one way to ecify knowledge 4 specify knowledge
Kinship domain • Write down what we know (what we want to be in the KB) – One’s mother is one’s female parent m, c Mother( m , c ) Female( m ) Parent( m, c ) m, c TheMotherOf( c ) = m Female( m ) Parent( m, c ) – One’s husband is one’s male spouse w, h Husband( h, w ) Male( h ) Spouse( h, w ) – One is either male or female x Male( x )   Female( x ) – Parent-child relationship p, c Parent( p, c ) Child( c, p ) –G r a n d parent-grandchild relationship p gp g, c Grandparent( g, c )   p Parent( g, p ) Parent( p, c ) –E t c… ow we can reason about family relationships (How?) 5 Now we can reason about family relationships. (How?)

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Kinship domain (cont.) Assertions (“Add this sentence to the KB”) T ELL ( KB, m, c Mother( c ) = m Female( m ) Parent( m, c ) ) T ELL ( KB, w, h Husband( h, w ) Male( h ) Spouse( h, w ) ) T ELL ( KB, x Male( x )   Female( x ) ) LL KB emale(Mary) arent(Mary Frank) arent(Frank Ann) T ELL ( KB, Female(Mary) Parent(Mary, Frank) Parent(Frank, Ann) ) –N o t e : T ELL ( KB, S1 S2 ) T ELL ( KB, S1) and T ELL ( KB, S2) (because of and-elimination and and-introduction ) Queries (“Does the KB entail this sentence?”) A SK ( KB,
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## This note was uploaded on 02/22/2011 for the course CS 165A taught by Professor Su during the Spring '11 term at UCSB.

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Lecture-10 - Artificial Intelligence CS 165A 165A Thursday...

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