• To: mathgroup at smc.vnet.net
• Subject: [mg104791] Re: [mg104765] A Question about Combinatorica
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Tue, 10 Nov 2009 05:58:50 -0500 (EST)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <200911091044.FAA05613@smc.vnet.net>

```This does not require the Combinatorica package, at least in current
versions of Mathematica:

pts={{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}};

Permutatations[pts];  (* suppress output *)

Length[Permutations[pts]]
120

What do you mean "similarities"?  You have 5 different points (as you
can check by comparing the Length of Union[pts]).  So there are exactly
120 (== 5! ) distinct permutations of those 5 objects.

Marwa Abd El-Wahaab 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?
>
>
>
> Thanks
>
> Marwa Ali
>
>

--
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

```

• Prev by Date: Re: Re: Text cell formating blues. LineBreakWithin,
• Next by Date: Re: Mathematica skill level snippet(s)