Matlab dynamically checks vector sizes... it does no static checking as far as I know... I dont know about maple etc... but as I said, matlab is the predominant tool in this area (at least in engineering) I suspect maple may have more of a following amongst mathematicians. Besides... Haskell can do dependant types... It can certainly do sized vectors and matrixes (see Conor McBride's Faking it paper)... Keean.