 On a Finsler manifold, the contact form is defined by the analogous formula
where "g""u" is the fundamental tensor (the hessian of the Finsler metric).Geometrically, the associated distribution of hyperplanes at the point "u" ∈ UT"x""M" is the inverse image under π* of the tangent hyperplane to the unit sphere in T"x""M" at "u".The volume form θ∧"d"θ"n"−1 defines a measure on "M", known as the kinematic measure, or Liouville measure, that is invariant under the geodesic flow of "M".