                &c_neg_one, Y(k,0),    &ldy,
                                       T(0,nb-1), &ione,
                           &c_one,     A(k,i),    &ione );
            
            // Apply I - V * T' * V' to this column (call it b) from the
            // left, using the last column of T as workspace, w.
            //
            // Let  V = ( V1 )   and   b = ( b1 )   (first i-1 rows)
            //          ( V2 )             ( b2 )
            // where V1 is unit lower triangular
            
    