Generating a Permutation Matrix P for All Permutations of A

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Discussion Overview

The discussion revolves around the generation of a permutation matrix P that, when applied to a matrix A, will yield the next permutation of A in a cyclic manner through all possible permutations. The inquiry includes theoretical aspects of permutations and their representation in matrix form.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant seeks a permutation matrix P that can cyclically permute another matrix A through all its permutations.
  • Another participant suggests calculating P raised to the factorial of the size of A, referencing specific examples of permutation matrices.
  • A later post questions whether a single permutation can be recursively applied to cycle through all permutations, drawing a parallel to programming functions like C++'s next_permutation.
  • One participant asserts that for sizes greater than 2, such a permutation does not exist, as it would imply that the symmetric group Sm is cyclic, which it is not for m > 2.

Areas of Agreement / Disagreement

Participants express differing views on the existence of a permutation that can achieve the desired cyclic behavior for sizes greater than 2, indicating a lack of consensus on the feasibility of the original inquiry.

Contextual Notes

There are assumptions regarding the properties of permutation matrices and the structure of symmetric groups that remain unresolved. The discussion does not clarify the implications of these assumptions on the feasibility of the proposed methods.

Who May Find This Useful

Readers interested in permutation matrices, group theory, and computational methods for generating permutations may find this discussion relevant.

xnull
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Hello!

I was wondering if there is a way to generate a permutation matrix P such that each application of P to another matrix A will find the "next" permutation of A. I'm looking for a way to generate a permutation matrix P (size m x m) such that applying it m! times to A (m x m) returns A (after having rolled through all possible permutations of A).

Am I looking for something I'm not going to be able to find?

Thanks!
 
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If I understood you correctly you are trying to calculate P^{(m!)}, where P is a permutation matrix. One way I can think of is to use the http://www.ece.cmu.edu/~smart/examples/cycle/cycle.html" , e.g. (4,1,3,2) stands for the matrix

<br /> \begin{bmatrix}<br /> 0 &amp; 0 &amp; 1 &amp; 0 \\<br /> 0 &amp; 0 &amp; 0 &amp; 1 \\<br /> 0 &amp; 1 &amp; 0 &amp; 0 \\<br /> 1 &amp; 0 &amp; 0 &amp; 0 \\<br /> \end{bmatrix}<br /> [/itex]<br /> <br /> (See also <a href="http://en.wikipedia.org/wiki/Permutation_matrix#Examples&quot;" target="_blank" class="link link--external" rel="nofollow ugc noopener">http://en.wikipedia.org/wiki/Permutation_matrix#Examples&quot;</a>)<br /> <br /> Then you have to calculate (4,1,3,2)^(m!) = (4,1,3,2)^(4!). You can use the program http://www.gap-system.org/&quot; and type into the command line: (4,1,3,2)^24 <br /> (see also http://people.math.jussieu.fr/~jmichel/htm/CHAP020.htm&quot; )<br /> <br /> There is a probably a theorem to calculate (a1,a2,...,am)^(m!).
 
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Let me ask it another way...

Is there some permutation that can be done to a list of elements such that the recursive application of that permutation to that list will cycle through all possible permutations?

Basically I'd like something like C++'s next_permutation (but without having each application of the function permute the input list in a different manner than the previous one).

[After experimenting I think I'm looking for something that doesn't exist?]

Thank you to everyone who has replied so far.
 
Indeed, for size m > 2, this does not exist, because it would imply that Sm is a cyclic group (i.e. generated by one element), which it is not for m > 2.
 
Oh phoey!

Thank you Moo of Doom (and the greater whole that is PF).
 

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