  The solvability and stability analysis of linear time invariant systems of
delay differential-algebraic equations (DDAEs) is analyzed. The behavior
approach is applied to DDAEs in order to establish characterizations of their
solvability in terms of spectral conditions. Furthermore, examples are
delivered to demonstrate that the eigenvalue-based approach to analyze the
exponential stability of dynamical system is only valid for a special class of
DDAEs, namely non-advanced. Then, a new concept of weak stability is proposed
and studied for DDAEs whose matrix coefficients pairwise commute.
