2018-05-11 19:54:10 +0100 commented question span of a matrixspace @tmonteil done! 2018-05-11 19:52:36 +0100 received badge ● Editor (source) 2018-05-11 14:12:54 +0100 received badge ● Student (source) 2018-05-11 10:28:32 +0100 asked a question span of a matrixspace given a matrix subspace of sparse matrices over a ring Q M=MatrixSpace(Q,1000,1000, sparse=True) I need a way to define the subspace N of M given a list of matrices of M I tried to turn matrices into lists and use the VectorSpace category, however my matrices are sparse matrices, and this takes very long def lista(A): #converts a matrix into a list return A.list() def coor(P): # for the determined base B, it gives the coordinate vector of a matrix P[0] A=base(P[1][1]) k=len(P[1][1]) V=VectorSpace(Q,2**(2*k), sparse=True) #I would like to work with MatrixSpace instead B=[] #this will be my basis for i in range(len(A)): a=A[i][0] B.append(V(lista(a))) W=W=V.span_of_basis(B) #I dont know if this function exists in MatrixSpace p=W.coordinate_vector(V(lista(P[0]))) return p