Re: A Question about Combinatorica
- To: mathgroup at smc.vnet.net
- Subject: [mg102684] Re: [mg102627] A Question about Combinatorica
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Tue, 18 Aug 2009 06:11:01 -0400 (EDT)
- Organization: Mathematics & Statistics, Univ. of Mass./Amherst
- References: <200908170804.EAA27022@smc.vnet.net>
- Reply-to: murray at math.umass.edu
Sorry, but your questions is unclear. There are 5!, that is, 120,
permutations of a list of length 5. And that is what Permutations and
Combinatorica`MinimumChangePermutations` both give you.
What does 60 have to do with it?
Marwa Abd El-Wahaab wrote:
> Dear Sir,
> I have a question about having five letters like {A, B, C, D, E}. In order
> to get all possibilities, we have 5! possible cases like ABCDE,
> EABCD,.......etc
>
> The number of these possibilities are 120. How and why this number becomes
> 60 by dividing by 2 ?
>
> What are 60 possibilities & how extract them from 120?
>
> I used this function to get 120:
>
> MinimumChangePermutations[{A,B,C,D,E}]
>
> What should I do after this to get 60?
>
> Thanks too much
>
> I really need your help
>
> *Marwa Ali Abd El Wahaab*
> *Teaching Assistant*
> Faculty of Engineering
> Mansoura University
>
>
--
Murray Eisenberg murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower phone 413 549-1020 (H)
University of Massachusetts 413 545-2859 (W)
710 North Pleasant Street fax 413 545-1801
Amherst, MA 01003-9305
- References:
- A Question about Combinatorica
- From: Marwa Abd El-Wahaab <m.a.elwahaab@gmail.com>
- A Question about Combinatorica