Sep 25, 2006
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- More on predicate logic
	- cscourse(x)
	- loves(x,y)

- Relations between predicates and relations
	- predicate: function that returns true/false of arguments
	- relation: explicitly lists argument tuples that are true

- Use of quantifiers
	- universal
	- existential

- Examples of modeling
	- The pope loves everybody.
	- Person X loves somebody.
	- Nobody loves person Y.
	- Person X loves at least two people.
	- Person X loves at least three people.
	- Person X loves exactly two people.
	- Person X loves at most two people.
	- Love is symmetric.
	- Love is not symmetric.

- A solved problem
	- Given
		- Whoever can read is literate.
		- Dolphins are not literate.
		- Some Dolphins are intelligent.
	- Prove
		- Some who are intelligent cannot read.


- Convert predicate logic statements to clauses
	- Use Skolem constants/Skolem functions 
		to denote existentially quantified variables
	- eliminate universally quantified variables

- Clauses are also called
	- wffs (well formed formulas)

- Using resolution to prove in predicate logic
	- need unification
	- negate the goal

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