  The implementation of Einstein's principle of equivalence in Koopman-von
Neumann (KvN) mechanics is discussed. The implementation is very similar to the
implementation of this principle in quantum mechanics. This is not surprising,
because KvN mechanics provides a Hilbert space formulation of classical
mechanics that is very similar to the quantum mechanical formalism.
  Both in KvN mechanics and quantum mechanics, a propagator in a homogeneous
gravitational field is simply related with a free propagator. As a result, the
wave function in a homogeneous gravitational field in a freely falling
reference frame differs from the free wave function only in phase.
  Fisher information, which quantifies our ability to estimate mass from
coordinate measurements, does not depend on the magnitude of the homogeneous
gravitational field, and this fact constitutes the formulation of Einstein's
principle of equivalence, which is valid both in quantum mechanics and KvN
mechanics.
