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#1 2008-06-05 21:35:49

tony123
Member
Registered: 2007-08-03
Posts: 229

Determine A.

Let G = {M1, M2, ... , Mr} denote the set of n × n permutation matrices (those matrices which have only zeroes and ones as entries, and whose row and column sums are all one), and let A = (M1 + M2 + ... + Mr) / r denote the average of these matrices. Determine A.

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#2 2008-06-06 06:08:46

TheDude
Member
Registered: 2007-10-23
Posts: 361

Re: Determine A.

There are n! total matrices in the set G.  The total sum of every element in a given matrix is n, which means that the total sum of every element in all of the matrices in G is n * n!.  Dividing by n!, the total number of matrices in G, we find that the total sum of every element in A is n.  Every element will have the same value, so this means that A is an nXn matrix where every element has the value 1/n.


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