 It is bounded by the "Bernstein inequality"

A module whose dimension attains the least possible value, "n", is called "holonomic".The "A"1("K")-module "M" = "A"1("K")/"A"1("K")"P" (see above) is holonomic for any nonzero differential operator "P", but a similar claim for higher-dimensional Weyl algebras does not hold.As mentioned above, modules over the Weyl algebra correspond to "D"-modules on affine space.