Jesus M. Castagnetto | 1 Apr 17:33 2007
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Re: [PEPr] Comment on Math::Math_Combinatorics

Just as a reference. For combinations and permutations there exist some other
variations, for example the "Complete Permutation" (or Derangement), and such
other weirdness.

See:

http://mathworld.wolfram.com/Permutation.html
http://mathworld.wolfram.com/Derangement.html
http://mathworld.wolfram.com/AlternatingPermutation.html
http://mathworld.wolfram.com/CircularPermutation.html
http://mathworld.wolfram.com/Combination.html
http://mathworld.wolfram.com/BinomialCoefficient.html
... etc.

Caveat: I had not looked in detail at your package. My net connection right now
is quite flaky.

Cheers.

--- David Sanders <dsanders <at> baselinesolutions.com.au> wrote:

> 
> I was thinking more of having repitition as an option.  Wiki *said* the
> definition can be either with or without repitition for both combinations
> and permutations.  (Now this is what I don't like about wiki: Someone has
> deleted the "Permutations without Repitition" sub-section without even
> providing a reason.  See the history tab)
> 
> 
> >
> > However, there's a topic to think about - repetitions. The original
> > definition of combination in mathematics implies that the elements have
> > to be unique, i.e. the combinations of the set {A, A, B} are the same as
> > these of {A, B}, of {A, A, A, A, B}, etc. Nevertheless, the term
> > "combination with repetition" exists. I will try to take a look in my
> > university courses on combinatorics during the weekend, because I'm
> > uncertain what is the correct behaviour that has to be followed in the
> > package.
> >
> 
> 
> -- 
>     David Sanders
>     shangxiao
> 
> -- 
> PEAR Development Mailing List (http://pear.php.net/)
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> 
> 

--
Jesus M. Castagnetto (jcastagnetto <at> yahoo.com)
Web site: http://www.castagnetto.org/
Research: http://metallo.scripps.edu/
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Gmane