What is constructive induction and how is it used to solve recursive equations?

  • Context: Graduate 
  • Thread starter Thread starter Dragonfall
  • Start date Start date
  • Tags Tags
    Induction
Click For Summary

Discussion Overview

The discussion revolves around the concept of "constructive induction" in the context of solving recursive equations, specifically examining a recurrence relation and its complexity classification as \Theta(n). Participants seek clarification on the method and its application to the given recursive equation.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant requests an explanation of "constructive induction" and its application to a specific recursive equation.
  • Another participant questions the ability to prove that the recurrence is \Theta(n) without a clear definition of \Theta(n), suggesting that T(3) does not equal \Theta(3) but rather \Theta(3) + 2.
  • A third participant clarifies that \Theta(n) refers to a function within the complexity class \Theta(n), which is defined as the intersection of O(n) and \Omega(n).

Areas of Agreement / Disagreement

Participants express differing views on the definition and implications of \Theta(n) in the context of the recursive equation, indicating a lack of consensus on the proof of the recurrence's complexity classification.

Contextual Notes

There is ambiguity regarding the definition of \Theta(n) as used in the discussion, which may affect the understanding of the recursive equation's classification. The relationship between T(3) and \Theta(3) is also contested.

Dragonfall
Messages
1,023
Reaction score
5
Can someone explain this "constructive induction" needed to solve recursive equations?

For example, use "constructive induction" to show that the following is \Theta (n)

T(n) = 1 \leftrightarrow n = 1,2
T(n) = T\lceil n/4\rceil + T \lceil 2n/3\rceil + \Theta (n) \leftrightarrow n > 2
 
Last edited:
Mathematics news on Phys.org
Anyone? This is kinda urgent.
 
Dragonfall said:
Can someone explain this "constructive induction" needed to solve recursive equations?

For example, use "constructive induction" to show that the following is \Theta (n)

T(n) = 1 \leftrightarrow n = 1,2
T(n) = T\lceil n/4\rceil + T \lceil 2n/3\rceil + \Theta (n) \leftrightarrow n > 2

Since you haven't said what \Theta(n) is, I don't see how any method can "prove" that is \Theta(n).

Whatever \Theta(n) is, T(3) is definitely not equal to \Theta(3), it is equal to \Theta(3)+ 2.
 
\Theta (n) in the recurrence is "some function" in the complexity class \Theta (n).

The complexity class \Theta (n) is the intersection of O(n) and \Omega (n).
 
Last edited:

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K