Chapter 4 Predicate Logics
Representing simple facts in logic The End It is raining. RAINING If it is raining then it is not sunny. RAINING ~ SUNNY All men are motal. MORTALMAN man(mortal) X : man(X) mortal(X) 1. Change sentences 1–8 on page 134 to predicate logic. 2. prove ~loyalto(Marcus,Caesar) on page 136 Fig. 5.2 344-471 AI & ES Chapter 4
Representing Instance and Isa Figure 5.3 page 138. : representing class membership 344-471 AI & ES Chapter 4
Computable functions and predicate The End Figure 5.4 page 142. :a set of facts about Marcus 344-471 AI & ES Chapter 4
Computable functions and predicate Figure 5.5 page 143. : Prove Marcus is dead 344-471 AI & ES Chapter 4
Propositional Logic Given Axioms Converted to Clause Form P P (P Q) R ~P v ~Q v R (S v T) Q ~S v Q ~T v Q T T 344-471 AI & ES Chapter 4
EX05EX05 can_swim can_swim(What) , predicates type(symbol, symbol) is_a(symbol, symbol) lives(symbol, symbol) can_swim(symbol) goal can_swim(What) , write("A ", What, " can swim."). clauses type(ungulate, animal). type(fish, animal). is_a(zebra, ungulate). is_a(herring, fish). is_a(shark, fish). lives(zebra, on_land). lives(frog, on_land). lives(frog, in_water). lives(shark, in_water). can_swim(Y) :- type(X, animal) , is_a(Y, X) , lives(Y, in_water). 344-471 AI & ES Chapter 4
predecessor Z X Y parent parent sister For any X and Y, X is a sister of Y if Both X and Y have the same parent, and X is a female. Sister(X,Y) :- parent(Z,X), parent(Z,Y), female(X). 344-471 AI & ES Chapter 4
predecessor A B C D E parent parent parent parent 344-471 AI & ES Chapter 4
predecessor A B C D E predecessor(X,Z) :- parent(X,Y), parent(Y,Z). parent(Y1,Y2), parent(Y2,Z). parent B parent C predecessor(X,Z) :- parent(X,Y1), parent(Y1,Y2), parent(Y2,Y3), parent(Y3,Z). parent D parent E 344-471 AI & ES Chapter 4
Parent1.Pro parent(jim,joe). 344-471 AI & ES Chapter 4 predicates parent(symbol,symbol) predecessor(symbol,symbol) clauses parent(pam,bob). parent(tom,bob). parent(bob,ann). parent(ann,jim). parent(jim,joe). parent(joe,john). parent(john,jack). parent(tom,liz). pam bob ann jim joe john jack predecessor(X,Z) :- parent(X,Z). predecessor(X,Z) :- parent(X,Y), parent(Y,Z). predecessor(X,Z) :- parent(X,Y1),parent(Y1,Y2),parent(Y2,Z). predecessor(X,Z) :- parent(X,Y1),parent(Y1,Y2),parent(Y2,Y3) parent(Y3,Z). 344-471 AI & ES Chapter 4
predecessor A B C D E For all X and Z, X is a predecessor of Z if there is a Y such that 1. X is a parent of Y and 2. Y is a predecessor of Z. A parent B parent C parent D parent E 344-471 AI & ES Chapter 4
Parent2.Pro parent(jim,joe). predecessor(X,Z) :- parent(X,Z). predicates parent(symbol,symbol) predecessor(symbol,symbol) clauses parent(pam,bob). parent(tom,bob). parent(bob,ann). parent(ann,jim). parent(jim,joe). parent(joe,john). parent(john,jack). parent(tom,liz). predecessor(X,Z) :- parent(X,Z). predecessor(X,Z) :- parent(X,Y), predecessor(Y,Z). 344-471 AI & ES Chapter 4
ISA Relationship isa isa isa isa isa isa isa isa isa isa isa Animal kingdom Plant kingdom isa isa isa Animal Human plant isa isa isa isa Dog Cat Suwit Sunee Flower isa isa isa isa Toop Mew Rose Carnation 344-471 AI & ES Chapter 4
isa1.Pro 344-471 AI & ES Chapter 4 is(X,Z) :- isa(X,Z). predicates isa(symbol,symbol) is(symbol,symbol) clauses isa(human,animal_kingdom). isa(plant,plant_kingdon). isa(flower,plant). isa(rose,flower). isa(carnation,flower). isa(suwit,human). isa(sunee,human). isa(dog,animal). isa(animal,animal_kingdom). isa(cat,animal). isa(toop,dog). isa(mew,cat). isa(white,cat). is(X,Z) :- isa(X,Z). is(X,Z) :- isa(X,Y), is(Y,Z). 344-471 AI & ES Chapter 4
bear.Pro ?black(X),big(X) ?brown(X),big(X) ?big(X),black(X) predicates big(symbol) small(symbol) brown(symbol) black(symbol) gray(symbol) dark(symbol) clauses big(bear). big(elephant). small(cat). brown(bear). black(cat). gray(elephant). dark(Z) :- black(Z). dark(Z) :- brown(Z). ?black(X),big(X) ?brown(X),big(X) ?big(X),black(X) ?black(X), big(X) No solution ?brown(X),big(X) X=bear ?big(X),black(X) 344-471 AI & ES Chapter 4
One that would have the fruit must climb the tree