CSE 607 Homework #2
(Due date: March 3, 2003)
Problem1. The following sentences appear in a tableau with the indicated polarity.
Remove all quantifiers(show the force and polarity of terms in the sentences).
1.
y)]x.P(x,y.[
2.
] q(y)]x) x).P(y,y.[([
3.
] z) y.P(y,z.[
4.
] Q(a)x.R(x)[
5.
] z)] z.Q(x, y)y.P(x,[.[ x
6.
x)]y.P(y,x.y)y.P(x,x.[
Problem 2. If possible, find a most general unifier for the following expressions. If they
can not be unified, say why.
1. P(f(a), y, z) and P(x, y, h(b)) where x, y and z are variables and a and b are constants
2. g(f(a)) and g(f(b)) where a and b are constants
3. Q(g(f(x)), b) and P(x, y) where x and y are variables and b is a constant
4. f(a) and x where x is a variable and a is a constant