They are certainly different.
2 comb 3
0 1
0 2
1 2
2 perm 3
0 1 2
0 2 1
1 0 2
In general, for n of m permutations and n of m combinations, the
permutations are going to be longer (length m instead of length n).
But the number of distinct items will be the same.
--
Raul
On Tue, Jun 26, 2012 at 2:09 PM, Devon McCormick <devon...@gmail.com> wrote:
> I thought that in the usual mathematical definition, combinations and
> permutations differ: for permutations, order matters; for
> combinations, it does not. Under this definition, the combinations of
> 3 things is just " i. 3 " - assuming we don't allow replacement? If
> we do allow replacement, the permutations of 3 things are given by "
> {3$<i.3 " and the combinations by something like " ~./:~&.>,{3$<i.3 ".
>
> Does this seem right?
>
> On Tue, Jun 26, 2012 at 12:51 PM, Raul Miller <rauldmil...@gmail.com> wrote:
>> Note that the number of combinations and the number of permutions are the
>> same.
>>
>> And, perm is just: ! A.&i. ]
>>
>> It seems like there ought to be a way of putting the permutations in 1
>> to 1 correspondence with the combinations (to give us a concise
>> expression for combinations).
>>
>> --
>> Raul
>>
>> On Tue, Jun 26, 2012 at 12:41 PM, ed bierly <ebie...@gmail.com> wrote:
>>> yes combinations not permutations
>>> thought there might be a way that didn't loop
>>> thank you for the references
>>>
>>> On Tue, Jun 26, 2012 at 12:30 PM, R.E. Boss <r.e.b...@planet.nl> wrote:
>>>
>>>> 4 comb 10
>>>>
>>>>
>>>> R.E. Boss
>>>>
>>>>
>>>> > -----Oorspronkelijk bericht-----
>>>> > Van: programming-boun...@jsoftware.com [mailto:
>>>> programming-boun...@jsoftware.com] Namens ed bierly
>>>> > Verzonden: dinsdag 26 juni 2012 18:15
>>>> > Aan: programming@jsoftware.com
>>>> > Onderwerp: [Jprogramming] permutation list
>>>> >
>>>> > what is the best way to get this list of 210 vectors?
>>>> >
>>>> > 4!10
>>>> > ----------------------------------------------------------------------
>>>> > For information about J forums see http://www.jsoftware.com/forums.htm
>>>>
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>
>>> ----------------------------------------------------------------------
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>
>
>
> --
> Devon McCormick, CFA
> ^me^ at acm.
> org is my
> preferred e-mail
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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