Slide 11
Slide 11 text
൱ఆͷఆٛɿ¬A = A → ⊥
⊥ʢϘτϜʣͷಋೖ
⊥ ಛघͳ໋ه߸
௨ৗͷݪࢠ໋ p, q, r, . . . ͱผʹɺܗࣜݴ
ޠͷఆٛʹ໌ࣔతʹՃ͢Δ
໋ʢจʣͷؼೲతఆٛʢվగ൛ʣ
(1) t1
= t2
ʢt1
, t2
߲ʣจ
(1’) ⊥ จʢಛघ໋ه߸ʣ
(2) A, B ͕จ ⇒ (A ∧ B) จ
(3) A, B ͕จ ⇒ (A → B) จ
(4) A, B ͕จ ⇒ (A ∨ B) จ
(5) ্هҎ֎จͰͳ͍
¬A ͷఆٛ
¬A A → ⊥ ͷུه
¬A := A → ⊥
¬¬A := (A → ⊥) → ⊥
ʮA ΛԾఆ͢Δͱໃ६͢Δʯ
= A ͔Β ⊥ ͕ূ໌Ͱ͖Δɺ
ͱ͍͏ҙຯʹͳΔʢޙͰʣ
ݱ࣌Ͱͷҙ
⊥ ʹର͢Δਪنଇ༩͑ͳ͍
⊥ Λ݁ͱͯ͠ಋग़͢Δنଇɺ⊥ Λ
લఏͱͯ͠͏نଇࠓճಋೖ͠ͳ͍
ՊֶֶՊֶ࢙ (ԋश) ཧֶʢલظʣ ୲ɿా෦ढ़հ 11