f [v1 ... vn] laplace0 g poly f ; string v1 ... vn ; poly g; array of poly f ; string v1 ... vn ; array of poly g; g is the lapalce transform of f with respect to variables v1, ..., vn. Example: (x Dx + y Dy + z Dz). [(x) (y) (Dx) (Dy)] laplace0 x --> -Dx, Dx --> x, y --> -Dy, Dy --> y.