離散數學chap 3 Recursive 觀念

Cindy Li
4 min readJan 9, 2021

§3–1 Recurrence Relations
▪Definition & Example
▪The Fibonacci sequence
▪Modeling with Recurrence Relations

§3–2 Closed-Form Solutions and Induction
▪Guessing a Closed-Form Solution 猜
▪Polynomial Sequences: Using Differences
▪Inductively Verifying a solution 數學歸納法

§3–3 Recursive Definitions
▪Definition & Ex.
▪Writing Recursive Definition
▪Recursive Geometry
//▪Recursive Jokes

§3–4 Proof by Induction
▪The Principle
▪Ex.
▪Strong Induction
▪Structural induction

§3–5 Recursive Data Structures
▪Lists
▪Efficiency
▪Binary Search Trees Revisited

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§3–1 Recurrence Relations

Recurrence Relation

Evaluation:
TopDown evaluation

BottomUp evaluation

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§3–2 Closed-Form Solutions and Induction
▪Guessing a Closed-Form Solution

▪Polynomial Sequences: Using Differences

▪Inductively Verifying a solution

=======================================

§3–3 Recursive Definitions

▪Definition & Ex.

▪Writing Recursive Definition

▪Recursive Geometry
//▪Recursive Jokes

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§3–4 Proof by Induction
▪The Principle of Induction

▪Ex.

▪Strong Induction

Example — — — — — —

強數學歸納法(The Principle of Strong Mathematical induction)
對一含有自然數n之命題,若我們能證明:
1.n=n0時,命題成立。
2.假設n0<=n<=K命題成立時,n=k+1命題亦成立。
則在n>=n0時,此命題皆可成立。

例:
我們欲證明大於或等於2的正整數為質數或質數的乘積
1.當n=2時,2為質數,故命題成立。
2.假設2<=n<=k時,命題成立。

考慮整數k+1的情況,若k+1為質數,命題成立。

或k+1非質數,則k+1可分解為p,q,其中p<=k,且q<=k。

根據假設,p及q必為質數或質數之乘積,故k+1亦為質數的乘積。

綜上所述,k+1為質數或質數之乘積。

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▪Structural induction

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§3–5 Recursive Data Structures
▪Lists

▪Efficiency

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