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Re: permutations?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg46488] Re: permutations?
  • From: "Bo Le" <bole79 at email.si>
  • Date: Fri, 20 Feb 2004 00:29:39 -0500 (EST)
  • References: <c11sc1$n64$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Voila,


In[1]:=
PickMyPermutations[toPermutate_,start_,end_]:=
  Module[{lst=Permutations[toPermutate]},
    Select[lst,MemberQ[start,First[#]]&&MemberQ[end,Last[#]]&]
    ]
In[2]:=
PickMyPermutations[{a,b,c,d},{a,b},{d}]
Out[2]=
{{a,b,c,d},{a,c,b,d},{b,a,c,d},{b,c,a,d}}



Borut
Slovenia


"sean kim" <sean_incali at yahoo.com> wrote in message news:c11sc1$n64$1 at smc.vnet.net...
> I think this is a permutation problem. but i'm not sure. do correct
> me.
>
> let's say you have...
>
> a, b, c, d, e   and...
>
> a', b', c', d', e'
>
> what are the possible combination will go from a( or a' ) to e ( or
> e')
>
> so that you get...
>
> {a b c d e}, {a b c d e'}, {a b c d' e}, {a b c d' e'}, {a b c' d e},
> { a b c' d' e}, {a, b, c' d e'}, {a, b, c' d' e'}....so on
>
> I have 32 from doing it the brute force way by hand.  how do i do that
> with Mathematica? I don't think it's fully connected graph.  because a only
> connects to downstream b or b'
>
> also... what kinda problem is described above?
>
> Thank you all very much in advance for any thoughts and comments.
>
> sean
>


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