[GAP Forum] GAP permutation question

[Dima Pasechnik]

Dear all, dear David,

When L1, L2 are 0-1 matrices, one can use the package GRAPE to construct
(bipartite) graphs from them, and test them for isomorphism (such a test, if
successful, returns an isomorphism, too)

As GRAPE does not work with edge-coloured graphs, for more general matrices
this won't work, at least not out of the box.
One can think of constructing edge-coloured bipartite graphs, then their
vertex-coloured line graphs, and test the latter for the isomorphism. (GRAPE
can deal with vertex colourings).

One can probably use the general GAP backtracking on permutation groups, but
I doubt that this will be feasible for big matrices...

regards,
Dima



On 3/26/06 5:44 AM, "David Joyner" <wdjoyner at comcast.net> wrote:

> Hello all:
> 
> Let L1, L2 be lists of objects (lists of vectors or lists of strings).
> Is there a GAP function which returns a permutation which
> send L1 to L2, if one exists, and "false" otherwise?
> 
> In case L1 = L2 = columns of a matrix M then the
> function could be paired with the MatrixAutomorphism group of
> M to return an "isomorphism" between two matrices.
> 
> - David Joyner
> 
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-- 
Dima Pasechnik
http://www.ntu.edu.sg/home/dima/