  Let $M$ be a closed symplectic manifold and $L \subset M$ a Lagrangian
submanifold. Denote by $[L]$ the homology class induced by $L$ viewed as a
class in the quantum homology of $M$. The present paper is concerned with
properties and identities involving the class $[L]$ in the quantum homology
ring. We also study the relations between these identities and invariants of
$L$ coming from Lagrangian Floer theory. We pay special attention to the case
when $L$ is a Lagrangian sphere.
