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CS 416
Artificial Intelligence
Lecture 11
Logical Agents
Chapter 7
Midterm Exam
• Midterm will be on Thursday, March 13th
• It will cover material up until Feb 27th
Reasoning w/ propositional logic
• Remember what we’ve developed so far
– Logical sentences
– And, or, not, implies (entailment), iff (equivalence)
– Syntax vs. semantics
– Truth tables
– Satisfiability, proof by contradiction
Logical Equivalences
• Know these equivalences
Reasoning w/ propositional logic
• Inference Rules
– Modus Ponens:
• Whenever sentences of form α=> βand αare given
the sentence βcan be inferred
–R
1: Green => Martian
–R
2: Green
– Inferred: Martian
Reasoning w/ propositional logic
•Inference Rules
– And-Elimination
• Any of conjuncts can be inferred
–R
1: Martian ^ Green
– Inferred: Martian
– Inferrred: Green
•Use truth tables if you want to confirm inference
rules
