predicate calculus

Intelligent Activity, in either human or machine, is achieved through the use of :
1.Symbol pattern to represent significant aspect of a problem space.
2.Operations on these patterns to generate potential solutions to problems.
3.Search to select a solution from among these possibilities.
Logic Consists Of
? A language: which tells us how to build up sentences in the language (i.e., syntax), and what the sentences mean(i.e., semantics)
? An inference procedure: which tells us which sentences are valid inferences from other sentences
Propositional Calculus Sentences
?Every propositional symbol and truth symbol is a sentence.
?Examples: true, P, Q, R.
?The negation of a sentence is a sentence.
? Examples: ?P, ? false.
?The conjunction, or and, of two sentences is a sentence.
? Example: P ? ?P.
Symbols And Terms
?1. Truth symbols true and false (these are reserved symbols)
?2. Constant symbols are symbol expressions having the first character lowercase.
? E.g., today, fisher
?3. Variable symbols are symbol expressions beginning with an uppercase character.
? E.g., X, Y, Z, Building
?4. Function symbols are symbol expressions having the first character lowercase. Arity: number of elements in the domain
? E.g., mother-of (bill); maximum-of (7,8)