Programming Languages III

1
Programming Languages III

• Shyh-Kang Jeng
• Department of Electrical Engineering/
• Graduate Institute of Communication Engineering
• National Taiwan University

2
Additional Reading

• S. Russell and P. Norvig, Artificial
  Intelligence A Modern Approach, Englewood
  Cliffs, NJ Prentice Hall, 1995

3
Logical Deduction

• Either Kermit is on stage or Kermit is sick
• Kermit is not on stage
• Kermit is sick
• Resolution Principle

4
Clause Form

• First-order predicate logic
• Implication
• Clause form

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Inconsistency
empty clause
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Automatic Reasoning using reduction ad absurdum

• Want to confirm a collection of statements
  implies the statement
• Same as contradicting the statement
• Apply resolution to the original statements and
  the statement until an empty clause occurs
• With inconsistent with the original
  statements, the original statements must imply

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Unification
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Prolog (1)

• PROgramming in LOGic
• A Prolog program consists of a collection of
  initial statements upon which the underlying
  algorithm bases its deductive reasoning
• Predicate
• A fact about its argument
• Examples

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Prolog (2)

• Rule
• Goal
• Proposed to the system and the system applies the
  resolution to try to confirm that the goal is a
  consequence of the initial statements

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Prolog Queries