命题逻辑与证明练习卷(附答案)

免费可打印的命题逻辑与证明练习卷:6 道题,从简单到考试水平,附答案。可打印或另存为 PDF。

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1.简单

写出了 (¬(p ∨ r) → q) ↔ (¬p → q) 的完整真值表。在多少行 N 中 p = 1 且 q = 0?

(¬(p ∨ r) → q) ↔ (¬p → q)
N =
2.简单
abc((a ↔ b) ∧ (a → c)) → (c ∨ b)111110101100011010001000

真值表中恰有一行使 ((a ↔ b) ∧ (a → c)) → (c ∨ b) 为假。点选这一行。

((a ↔ b) ∧ (a → c)) → (c ∨ b)
  1. 1a = 1, b = 1, c = 1
  2. 2a = 1, b = 1, c = 0
  3. 3a = 1, b = 0, c = 1
  4. 4a = 1, b = 0, c = 0
  5. 5a = 0, b = 1, c = 1
  6. 6a = 0, b = 1, c = 0
  7. 7a = 0, b = 0, c = 1
  8. 8a = 0, b = 0, c = 0
3.中等
pqrp ∧ ¬(r ∧ q)¬(p ∧ ¬(r ∧ q))(r → p) → ¬(p ∧ ¬(r ∧ q))111?110?101?100?011?010?001?000?

在其真值表的 8 行中,(r → p) → ¬(p ∧ ¬(r ∧ q)) 在多少行为真?把这个数记作 N。

(r → p) → ¬(p ∧ ¬(r ∧ q))
N =
4.中等
abca → (b → c)¬(a → (b → c))((b ↔ a) ∨ c) ∧ ¬(a → (b → c))111?110?101?100?011?010?001?000?

在其真值表的 8 行中,((b ↔ a) ∨ c) ∧ ¬(a → (b → c)) 在多少行为真?把这个数记作 N。

((b ↔ a) ∨ c) ∧ ¬(a → (b → c))
N =
5.困难
pqrq → (p ∨ r)qp111110101100011010001000

前提为 q → (p ∨ r); q、结论为 p 的论证是无效的。点选真值表中作为反例的那一行。

q → (p ∨ r)q∴ p
  1. 1p = 1, q = 1, r = 1
  2. 2p = 1, q = 1, r = 0
  3. 3p = 1, q = 0, r = 1
  4. 4p = 1, q = 0, r = 0
  5. 5p = 0, q = 1, r = 1
  6. 6p = 0, q = 1, r = 0
  7. 7p = 0, q = 0, r = 1
  8. 8p = 0, q = 0, r = 0
6.困难
∀x (A(x) ∧ ∀y ¬R(x, y))∃x (A(x) ∧ ∀y ¬R(x, y))∃x (A(x) → ∀y ¬R(x, y))∃x (¬A(x) ∧ ∃y R(x, y))

把否定完全移到内部之后,哪个命题与 ¬∀x (A(x) → ∃y R(x, y)) 等价?点选它。

¬∀x (A(x) → ∃y R(x, y))
  1. 1∀x (A(x) ∧ ∀y ¬R(x, y))
  2. 2∃x (A(x) ∧ ∀y ¬R(x, y))
  3. 3∃x (A(x) → ∀y ¬R(x, y))
  4. 4∃x (¬A(x) ∧ ∃y R(x, y))

答案

  1. 1. N = 2
  2. 2. a = 0, b = 0, c = 0
  3. 3. N = 5
  4. 4. N = 1
  5. 5. p = 0, q = 1, r = 1
  6. 6. ∃x (A(x) ∧ ∀y ¬R(x, y))

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