課程名稱︰邏輯
課程性質︰通識A4
課程教師︰傅皓政
開課學院:
開課系所︰
考試日期(年月日)︰2017/11/06
考試時限(分鐘):90
試題 :
一、請建構命題邏輯語言(提示:包括符號與形構規則兩個部分)。(10%)
(Construct a suitable language for propositional logic. Hint: two parts
involved, alphabets and formation rules)
二、請判斷下列陳述的真假,並且分別以T與F代表「真」與「假」。(10%)
(Please judge the following statements which are true or false. Notice,
please use the symbols "T" and "F" which stand for true and false
statements respectively.)
_ 1. 結論是矛盾句的論證可能是有效論證。
_ 2. 前提出現矛盾句的論證一定是有效論證。
_ 3. 前提與結論一致的論證可能是有效論證。
_ 4. 前提實際上為假而且結論實際上為真的論證一定是有效論證。
_ 5. 前提不可能全部為真的論證可能是無效論證。
_ 6. 有效論證中至少必須有一個前提實際上為真。
_ 7. 前提實際上為真而且結論實際上為假的論證可能是有效論證。
_ 8. 前提與結論都是偶真句的論證可能是有效論證。
_ 9. 前提與結論不一致的論證一定是有效論證。
_ 10. 前提與結論實際上為假的論證一定是無效論證。
三、請判斷下列句式哪些是恆真句、矛盾句或者是偶真句。你可以使用任何學過的方法,
包括真值表法、簡易真值表法或真值樹法,必須列出演算過程。(15%)
(Using some method (e.g. truth table, short-cut or tableaux system) shows
that each of the following formulae is tautology, contradiction, or
indeterminate formula. Computational process is required.)
(a) D → ((C Λ D) → D)
(b) ┐(H → G) Λ ┐(G → H)
(c) (K → (L → M)) → ((K → L) Λ (K → M))
四、請判斷下列各題中的兩個句式之間是蘊涵或是等值關係。如果是蘊涵關係,以φ╞ψ
表示;若為等值關係,則以╞φ←→ψ表示,必須列出演算過程。(15%)
(Using some methods determine the semantic relation between the following
formulae. If the entailment relation holds then show them of the form
φ╞ψ. On the other hand, show them of the form ╞φ←→ψ if they are
equivalent. Computational process is required.)
(a) M V (N → N) ; M V N
(b) (P Λ Q) V (Q Λ R) ; (┐P Λ ┐Q) V (┐Q Λ ┐R)
(c) ┐(┐A Λ ┐B) ; ┐B → A
五、請寫出等值於真值表中語句φ的DNF及CNF。(10%)
(Find out the DNF and CNF each which is equivalent to the following
formulae φ.)
(a) (b)
┌─┬─┬─┬─┐ ┌─┬─┬─┬─┐
│L│M│N│φ│ │G│H│K│φ│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│T│T│T│T│ │T│T│T│T│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│T│T│F│F│ │T│T│F│T│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│T│F│T│T│ │T│F│T│F│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│T│F│F│F│ │T│F│F│T│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│F│T│T│F│ │F│T│T│F│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│F│T│F│T│ │F│T│F│F│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│F│F│T│T│ │F│F│T│T│
├─┼─┼─┼─┤ ├─┼─┼─┼─┤
│F│F│F│F│ │F│F│F│T│
└─┴─┴─┴─┘ └─┴─┴─┴─┘
六、請以真值樹法證明下列語法序列是否為有效論證,若為無效論證請顯示其反例結構。
(20%)
(Please use tableaux system to prove whether each of the following
argument is valid. And specify a counterexample if it is invalid.)
(a) (Q V ┐P) → ┐R ; (P Λ Q) → R ├ (Q Λ R) → ┐P
(b) K → L ; K V (L ←→ K) ├ ┐K
七、請完成下列演算,作答時須連同題目寫在答案卷上。(10%)
(Please complete the following proofs. Notice: you should copy the whole
questions on your answer sheet.)
(a) 證明 ├ ┐A → (A → B)
(1) (┐B → ┐A) → (A → B) _______________
(2) ((┐B → ┐A) → (A → B)) →
(┐A → ((┐B → ┐A) → (A → B))) _______________
(3) ┐A → ((┐B → ┐A) → (A → B)) _______________
(4) (┐A → ((┐B → ┐A) → (A → B))) →
((┐A → (┐B → ┐A)) → (┐A → (A → B))) _______________
(5) (┐A → (┐B → ┐A)) → (┐A → (A → B)) _______________
(6) ┐A → (┐B → ┐A) _______________
(7) ┐A → (A → B) _______________
(b) 證明 ┐┐K ├ K
(1) ┐┐K _______________
(2) ┐┐K → (┐┐┐┐K → ┐┐K) _______________
(3) ┐┐┐┐K → ┐┐K _______________
(4) (┐┐┐┐K → ┐┐K) → (┐K → ┐┐┐K) _______________
(5) ┐K → ┐┐┐K _______________
(6) (┐K → ┐┐┐K) → (┐┐K → K) _______________
(7) ┐┐K → K _______________
(8) K _______________
八、古典邏輯的語意學有三個預設,其中的真值函映原則設定古典邏輯的運算符號都必須
是真值函映的運算符號,然而實際上有很多運算符號是非真值函映的運算符號,請舉
一個實例說明非真值函映的運算符號。(10%)
(There are three important postulates of the semantics of the classic
logic, one of them is the so-called the principle of truth-functionality.
Nonetheless we have many non-truth functional operators in our ordinary
language. Please take an non-truth functional operator to illustrate.)
Appendix: Rules of inference
命題邏輯公理系統(propositional logic axiomatic system)
公理(axioms):
(A1) φ → (ψ → φ)
(A2) (φ → (ψ → θ)) → ((φ → ψ) → (φ → θ))
(A3) (┐φ → ┐ψ) → (ψ → φ)
推論規則(rule of inference):
(MP) 從 φ 和(φ → ψ)成立,可以推論出 ψ 成立。