  In this short note, we derive dissipative conditions with slack variables for
a linear coupled differential-difference (CDDS) via constructing a Krasovskii
functional. The approach can be interpreted as a generalization of the Finsler
Lemma approach for standard LTI systems proposed previously in
\cite{de2001stability}. We also show that the proposed slack variables scheme
is equivalent to the approach based on directly substituting the system
trajectory $\dot{\bm{x}}(t)$, similar to the case of LTI system.
