Re: A Question of Permutations of Vectors of Bits

From: Simon G Best (s.g.best_at_btopenworld.com)
Date: 07/31/03 

Date: Thu, 31 Jul 2003 08:35:13 +0000 (UTC)

Mok-Kong Shen wrote:
>
> Mok-Kong Shen wrote:
>
>>Sorry, I remain confused. If the example P I gave is
>>of the kind what your problem is involved, then, in my
>>understanding, P IS a transposition. (In fact such a P
>>can also be obtained as a sequence of swaps of pairs of
>>elements.) If such a P is given (known), then linear
>>algebra can solve for x, if y is also given (known)..
>>(Or do you 'change' with your second post the problem of
>>the first?)

No, I didn't "'change'" the problem. I just realised that I hadn't
worded it very well.

> Addendum: Just to be clear: ANY permutation IS a
> transposition of the elements of the sequence involved.
> (There is no exception.)
>
> M. K. Shen

P doesn't necessarily transpose the bits within each vector.

For example, P could be such that P(00000000) = 01101011.

Another example: P could be

         ( 00 01 10 11 )
         ( 01 11 00 10 )

Simon

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