Dear Rahul, the expression [A,B] denotes a list with the two entries A and B. GAP does not understand that you want to write the two matrices next to each other.
In GAP a matrix is represented as a list of list. The rows of the matrix you are interested are the concatenations of the corresponding rows of A and B. So you can define gap> C := List([1..Length(A)], i -> Concatenation(A[i], B[i])); and then compute gap> Rank(C); Hope this helps. Sven Reichard TU Dresden On 03.03.2017 04:51, Rahul Kitture wrote: > Dear Experts, > > I had a simple question about rank of matrices over finite fields in GAP. > > Suppose A and B are matrices (over a finite field GF(p)), considered in GAP. > > Assume that A and B have *same number of rows*. > > Then I want to consider the matrix obtained by putting B after A (i.e. the > matrix [A B]; it has same number of rows as A; but number of columns is > (number of columns of A) + (number of columns of B)) and study rank of [A > B]. > > What is the command to do this? > > I did *gap > RankMat([A,B]); * > > But it was showing error. > > > Thanks in advance! > > -Rahul Kitture > HRI, Allahabad > _______________________________________________ > Forum mailing list > Forum@mail.gap-system.org > http://mail.gap-system.org/mailman/listinfo/forum > _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum