[GAP Forum] An elementary question about matrices

[Shaun Van Ault]

Josef,
   If M is the n-by-m matrix, and L is the subset of [1..m], then you 
can use:

TransposedMat(TransposedMat(M){L});

or, for a mutable version,

MutableTransposedMat(TransposedMat(M){L});

Note, you may obtaining the rows of M corresponding to L, by simply 
using M{L}, if L is a subset of [1..n].

Best wishes,
-Shaun

Josef Lauri wrote:
> Is there a function in GAP or one of its packages which, given an  n 
> \times m matrix A and a subset lst of [1..m], returns the submatrix of A 
> obtained from the columns of A indexed by lst?
> 
> Thank you.
> 
> Josef Lauri
> Department of Mathematics
> 
> _______________________________________________
> Forum mailing list
> Forum at mail.gap-system.org
> http://mail.gap-system.org/mailman/listinfo/forum