Gradient-like properties of distributed and discrete phase systems.
Global asymptotic behavior of control systems with periodic vector nonlinearities
and denumerable sets of equilibria is investigated. Distributed systems described
by integrodifferential Volterra equations and discrete systems described by
difference equations are examined. New kinds of Popov-type functionals and
Lyapunov-type sequences are offered. New frequency-domain criteria for gradient-like behavior
of the systems are obtained.