Knowledge and reasoning

어휘

English

Rules and consequences

Propositional logic: facts and rules ($P \to Q$); inference applies modus ponens. Forward chaining floods from the facts; backward chaining aims from the query — symbolic reasoning draws conclusions the data never saw.

{exercise:uni-cs1302-rules}

연습

Forward chaining starts from —

난이도 1/5 · 100코인 + 오늘 첫 완료 시 작은 보너스 추가

English

F1 Storm; F2 Weekend; R1 Storm → Delayed; R2 Weekend → HeavyTraffic; R3 HeavyTraffic → Delayed; R4 Delayed → RefundRisk. Forward chaining: wave one derives Delayed and HeavyTraffic, wave two RefundRisk.
Backward chain for RefundRisk: goal ← Delayed (R4) ← Storm (R1) ← fact: proved in three steps, R2/R3 never fire — goal-directed search.

{exercise:uni-cs1302-kb}

연습

The course KB derives RefundRisk in — waves

난이도 1/5 · 100코인 + 오늘 첫 완료 시 작은 보너스 추가

English

Every step is modus ponens on assumed rules, so derivations cannot invent falsehood; completeness (every consequence reachable) is the harder property.
To prove $Q$ by refutation: assume $\neg Q$, derive the empty clause by resolution — the machinery behind SAT solvers. The converse error ($P \to Q$ read as $Q \to P$) is the classic trap.

{exercise:uni-cs1302-sound}

연습

Modus ponens makes inference —

난이도 1/5 · 100코인 + 오늘 첫 완료 시 작은 보너스 추가