Difference between revisions of "Cantor set"

(New page: The '''Cantor set''' is equal to <math>C(0,1)</math>, where <math>C</math> is a recursively defined function: <math>C(a,b)=C\left(a, \frac{2a+b}{3}\right)\cup C\left(\frac{a+...)
 
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The '''Cantor set''' is equal to <math>C(0,1)</math>, where <math>C</math> is a [[recursion|recursively]] defined function: <math>C(a,b)=C\left(a, \frac{2a+b}{3}\right)\cup C\left(\frac{a+2b}{3},b\right)</math> and <math>C\left(a,a\right)=\{a\}</math>. Geometrically, one can imagine starting with the set [0,1] and removing the middle third, and removing the middle third of the two remaining segments, and removing the middle third of the four remaining segments, and so on ''ad infinitum''.
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The '''Cantor set''' <math>\mathcal{C}</math> is a [[subset]] of the [[real number]]s that exhibits a number of interesting and counter-intuitive properties.  It is among the simplest examples of a [[fractal]].
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The Cantor set can be described [[recursion|recursively]] as follows: begin with the set [0,1] and then remove the ([[open interval | open]]) middle third, dividing the [[interval]] into two intervals of length <math>\frac{1}{3}</math>. Then remove the middle third of the two remaining segments, and remove the middle third of the four remaining segments, and so on ''ad infinitum''.
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Equivalently, we may define <math>\mathcal{C}</math> to be the set of real numbers between <math>0</math> and <math>1</math> with a [[base number | base]] three expansion that contains only the digits <math>0</math> and <math>1</math>.
  
 
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Revision as of 10:42, 22 July 2009

The Cantor set $\mathcal{C}$ is a subset of the real numbers that exhibits a number of interesting and counter-intuitive properties. It is among the simplest examples of a fractal.

The Cantor set can be described recursively as follows: begin with the set [0,1] and then remove the ( open) middle third, dividing the interval into two intervals of length $\frac{1}{3}$. Then remove the middle third of the two remaining segments, and remove the middle third of the four remaining segments, and so on ad infinitum.

Equivalently, we may define $\mathcal{C}$ to be the set of real numbers between $0$ and $1$ with a base three expansion that contains only the digits $0$ and $1$.

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