Logic
∨,∨∧:⊕⊗¬∀∃
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Inference: agent will use knowledge and logic to provide inference
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Soundness: Only valid conclusions can be proven
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Completeness: All valid conclusions can be proven
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Predicate: a function that maps object args to T/F
- Feathers(bluebird) >>> True
Implication x implies y, ⇒
Conjunctions, Disjunctions, Negations, Implications
Conjunction
if an animal lays eggs and an animal flies than the animal is a bird
If Lays-eggs(animal)∧Flies(animal)⇒Then Bird(animal)
Disjunction
if an animal lays eggs or an animal flies than the animal is a bird
Lays-eggs(animal)∨Flies(animal)⇒Then Bird(animal)
If an animal flies and is not a bird, it is a bat
Flies(animal)∧¬Bird(animal)⇒Bat(animal)
Truth Tables
- Demorgan's law ¬(A∧B)==¬A∨¬B
- The outer not flips the inner operation
Kinda weird logic for "Implies" ⇒
| A | B | A⇒B |
|---|
| T | T | T |
| T | F | F |
| F | T | T |
| F | F | T |
A⇒B==¬A∨B
Rules of Inference
Modus Ponens
| x | Logic |
|---|
| Sentence 1 | P⇒Q |
| Sentence 2 | P |
| Sentence 3 | Q |
Modus Tollens
| x | Logic |
|---|
| Sentence 1 | P⇒Q |
| Sentence 2 | ¬Q |
| Sentence 3 | ¬P |
Resolution Theorem Proving
- Prove the opposite of what we're trying to prove
- Start by eliminating the thing you're trying to prove with the contrapositive in the full sentence