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Ranker [1199515] · MS 2022 · 쪽지

2026-06-15 21:50:19
조회수 90

연습문제 V

게시글 주소: https://orbi.kr/00078657833


1. (∃x)Bx → (∀x)(Dx → Ax)

2. (∃x)Dx → (∀x)(Ax → Cx) /(∃x)Bx → (∀x)(Dx → Cx)

    3. ~{(∃x)Bx → (∀x)(Dx → Cx)} A

4. ~{~(∃x)Bx ⋁ (∀x)(Dx → Cx)} 3, Impl.

5. ~~(∃x)Bx ⋀ ~(∀x)(Dx → Cx) 4, DM

6. (∃x)Bx ⋀ ~(∀x)(Dx → Cx) 5, DN

 13. Da  14. (∃x)Dx  15. (∀x)(Ax → Cx)  16. (∃x)Bx  17. (∀x)(Dx → Ax)  18. Da → Aa 12, DN

13, ∃I

2, 14, MP

6, Simp.

2, 16, MP

17, ∀E

      7. ~(∀x)(Dx → Cx) 8. (∃x)~(Dx → Cx) 9. ~(Da → Ca) 10. ~(~Da ⋁ Ca) 11. ~~Da ⋀ ~Ca 12. ~~Da 6, Simp.

7, QN

8, ∃E

9, Impl.

10, DM

11, Simp.

 19. Aa → Ca  20. Da → Ca  21. Ca 15, ∀E

18, 19, HS

13, 20, MP

 22. ~Ca  23. Ca ⋀ ~Ca 11, Simp.

21, 22, Conj. 

24. (∃x)Bx → (∀x)(Dx → Cx) 3-23, IP

rare-Lc0 rare-투디비

0 XDK (+0)

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