Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Any ideas on expanded results for SetPartitions in discrete-combinatoria

  • To: mathgroup at smc.vnet.net
  • Subject: [mg67062] Re: Any ideas on expanded results for SetPartitions in discrete-combinatoria
  • From: Peter Pein <petsie at dordos.net>
  • Date: Thu, 8 Jun 2006 04:53:55 -0400 (EDT)
  • References: <e66600$n62$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Ike schrieb:
> Looking for suggestions...
> 
> SetPartitions drops partitions that have "overlaps", any ideas on how to 
> modify or recreate a SetPartitions function that doesn't drop these?
> 
> For example
> 
> SetPartitions[{A,B,C}]
> 
> Generates:
> 
> 
> {{{A, B, C}}, {{A}, {B, C}}, {{A, B}, {C}}, {{A, C}, {B}}, {{A}, {B}, {C}}}
> 
> 
> What it is missing (for my needs) are the following:
> 
> {{A,B}, {B, C}}, {{A,C}, {B, C}}, {{A,B}, {A, C}}, {{A,B}, {B, C},{A,C}}
> 
> I have tried doing this:
> 
> SetPartitions[{A,A,B,B,C,C}] which adds them but then I need a quick way 
> to delete the subsets that have duplicate elemenets.
> 
> 
> Either way will get me where I need to be. But I can not figure it out.
>    
> Thanks in advance for any help.
> 
> Ike
> wde at pdx.edu
> 

Hi Ike,

  does
In[1]:=
Map[Union, SetPartitions[{A, A, B, B, C, C}], {0, 2}]
Out[1]=
{{{A, B, C}}, {{A}, {B, C}}, {{A}, {A, B, C}}, {{B}, {A, C}}, {{B}, {A, B, C}}, {{C}, {A, B}},
   {{C}, {A, B, C}}, {{A, B}, {A, C}}, {{A, B}, {B, C}}, {{A, B}, {A, B, C}}, {{A, C}, {B, C}},
   {{A, C}, {A, B, C}}, {{B, C}, {A, B, C}}, {{A}, {B}, {C}}, {{A}, {B}, {A, C}}, {{A}, {B}, {B, C}},
   {{A}, {B}, {A, B, C}}, {{A}, {C}, {A, B}}, {{A}, {C}, {B, C}}, {{A}, {C}, {A, B, C}},
   {{A}, {A, B}, {B, C}}, {{A}, {A, C}, {B, C}}, {{A}, {B, C}, {A, B, C}}, {{B}, {C}, {A, B}},
   {{B}, {C}, {A, C}}, {{B}, {C}, {A, B, C}}, {{B}, {A, B}, {A, C}}, {{B}, {A, C}, {B, C}},
   {{B}, {A, C}, {A, B, C}}, {{C}, {A, B}, {A, C}}, {{C}, {A, B}, {B, C}}, {{C}, {A, B}, {A, B, C}},
   {{A, B}, {A, C}, {B, C}}, {{A}, {B}, {C}, {A, B}}, {{A}, {B}, {C}, {A, C}}, {{A}, {B}, {C}, {B, C}},
   {{A}, {B}, {C}, {A, B, C}}, {{A}, {B}, {A, C}, {B, C}}, {{A}, {C}, {A, B}, {B, C}},
   {{B}, {C}, {A, B}, {A, C}}}

give the desired result?


Peter


  • Prev by Date: Re: Re: piecewise integration
  • Next by Date: Re: Re: Re: Colored Tick Labels?
  • Previous by thread: Any ideas on expanded results for SetPartitions in discrete-combinatoria
  • Next by thread: RE: [heur] Table through zero...strange