• To: mathgroup at smc.vnet.net
• Subject: [mg104817] Re: A Question about Combinatorica
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Tue, 10 Nov 2009 06:04:07 -0500 (EST)
• References: <hd8sgh\$60i\$1@smc.vnet.net>

```Dear Marwa Ali,

I'm not sure whether I totally understand what you want to achieve.
You can get all permutations of your list as follows:

Permutations[{{0., 0., 1.}, {0.181636, 0.559017,
0.809017}, {-0.769421, 0.559017,
0.309017}, {-0.769421, -0.559017, -0.309017}, {0.181636, \
-0.559017, -0.809017}}]

Of course each permutation contains the same set of points, just in a
different order. So, the SETS are all the same but the ORDERS are all
different. You need to define what you mean with deleting
similarities.

Cheers -- Sjoerd

On Nov 9, 12:56 pm, Marwa Abd El-Wahaab <m.a.elwah... at gmail.com>
wrote:
> Dear Sir
>
> I have a question about  permutations of 5 points in 3D space .
>
> These 5 points are on the surface of a sphere of radius =1.
>
> These points are:
>  { {0., 0., 1.},  {0.181636, 0.559017, 0.809017},  {-0.769421,
> 0.559017, 0.309017}, {-0.769421, -0.559017, -0.309017}, {0.181636,
> -0.559017, -0.809017} }
>
> My question:
>
> What are all possible permutations for these 5 points ?
>
> What are the permutations after delete similarities?
>