  This paper analyses the interplay between dissipativity and stability
properties in continuous-time infinite-horizon Optimal Control Problems (OCPs).
We establish several relations between these properties, which culminate in a
set of equivalence conditions. Moreover, we investigate convergence and
stability of the infinite-horizon optimal adjoint trajectories. The workhorse
for our investigations is a notion of strict dissipativity in OCPs, which has
been coined in the context of economic model predictive control. With respect
to the link between stability and dissipativity, the present paper can be seen
as an extension of the seminal work on least squares optimal control by Willems
from 1971. Furthermore, we show that strict dissipativity provides a conclusive
answer to the question of adjoint transversality conditions in infinite-horizon
optimal control which has been raised by Halkin in 1974. Put differently, we
establish conditions under which the adjoints converge to their optimal steady
state value. We draw upon several examples to illustrate our findings.
Moreover, we discuss the relation of our findings to results available in the
literature.
