  Givental's non-linear Maslov index, constructed in 1990, is a quasimorphism
on the universal cover of the identity component of the contactomorphism group
of real projective space. This invariant was used by several authors to prove
contact rigidity phenomena such as orderability, unboundedness of the
discriminant and oscillation metrics, and a contact geometric version of the
Arnold conjecture. In this article we give an analogue for lens spaces of
Givental's construction and its applications.
