Difference between revisions of "Iterated majority"

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== Definition ==
 
== Definition ==
Let <math>n = 3^k</math>. The '''iterated majority function''' f:\{-1,1\}^n \to \{-1,1\}</math> is a recursively-defined variation on the [[majority function]].
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Let <math>n = 3^k</math>. The '''iterated majority function''' <math>f:\{-1,1\}^n \to \{-1,1\}</math> is a recursively-defined variation on the [[majority function]]:
  
<math> f(x) = \begin{cases} maj(x), & if ~ n = 3 \\  
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<math> f(x) = \begin{cases} \textrm{maj}(x), & \textrm{if}~ n = 3 \\  
maj(f(x^{(1)}),f(x^{(2)}),f(x^{(3)}) & otherwise, \end{cases}</math>
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\textrm{maj}(f(x^{(1)}),f(x^{(2)}),f(x^{(3)}) & \textrm{otherwise}, \end{cases}</math>
  
 
where <math>x^{(1)} = (x_1,x_2\ldots x_{n/3})</math>, <math>x^{(2)} = (x_{n/3+1},\ldots x_{2n/3})</math> and <math>x^{(3)} = (x_{2n/3+1},\ldots x_{n})</math>
 
where <math>x^{(1)} = (x_1,x_2\ldots x_{n/3})</math>, <math>x^{(2)} = (x_{n/3+1},\ldots x_{2n/3})</math> and <math>x^{(3)} = (x_{2n/3+1},\ldots x_{n})</math>
 
  
 
== Properties ==  
 
== Properties ==  

Revision as of 13:37, 6 June 2019

Definition

Let [math]n = 3^k[/math]. The iterated majority function [math]f:\{-1,1\}^n \to \{-1,1\}[/math] is a recursively-defined variation on the majority function:

[math] f(x) = \begin{cases} \textrm{maj}(x), & \textrm{if}~ n = 3 \\ \textrm{maj}(f(x^{(1)}),f(x^{(2)}),f(x^{(3)}) & \textrm{otherwise}, \end{cases}[/math]

where [math]x^{(1)} = (x_1,x_2\ldots x_{n/3})[/math], [math]x^{(2)} = (x_{n/3+1},\ldots x_{2n/3})[/math] and [math]x^{(3)} = (x_{2n/3+1},\ldots x_{n})[/math]

Properties

  • TODO

References