用 Lexicon 翻译成谓词逻辑

Translation to Predicate Logic with Lexicon

如何将以下语句翻译成谓词逻辑:

"即使考官希望所有学生都能达到E级或更好的要求,但有人会得到较低的分数并感到失望。"

第一步是定义字母表。采用以下具有所需解释的一阶字母表:

Unary predicates:

  • S(x): "x is a student"
  • E(x): "x is an examiner"
  • G(x): "x is a grade"
  • D(x): "x is disappointed"

Binary predicates:

  • R(x, y): "x is a requirement for y"
  • B(x, y): "x is y or better"
  • O(x, y): "x receives y"

Ternary predicates:

  • H(x, y, z): "x hopes that y fulfills z"

e: Constant ("the grade E")

x, y, z, w: Variables

让我们把原来的说法分成两部分:

S1: "The examiner hopes all students will satisfy the requirements for grade E or better"

S2: "Somebody will receive a lower grade and be disappointed"

并使用定义的字母顺序写成:

S1: ∃x(E(x) ∧ ∀y(S(y) ⇒ ∃z∃w(R(z, e) ∧ B(w, z) ∧ H(x, y, w))))

S2: ∃x∃y(S(x) ∧ G(y) ∧ O(x, y) ∧ ¬B(y, e) ∧ D(x))

最后我们计算出原始语句,即:

S1 ∧ S2

请记住,这只是导致正确(令人满意)答案的解释之一。

希望对你有帮助