  Given a symplectic toric manifold, the moment maps of sub-circle actions can
be modified to be admissible functions in the sense of Hofer-Zehnder. By
exploiting the relationship between the period of Hamiltonian sub-circle
actions of a symplectic toric manifold and its Delzant polytope, we develop an
invariant of Delzant polytopes which gives a lower bound of the Hofer-Zehnder
capacity.
