The Kalman-Yakubovich-Popov lemma is a central result in systems and control theory which relates the positive semidefiniteness of a Popov function on the imaginary axis to the solvability of a linear matrix inequality. In this paper we prove sufficient conditions for the existence of a nonpositive solution to this inequality for differential-algebraic systems. Our conditions are given in terms...

A Comment on the Letter by Q. Li, M. Popov, A. Dimaki, A. E. Filippov, S. Kürschner, and V. L. Popov, Phys. Rev. Lett. 111, 034301 (2013). The authors of the Letter offer a Reply.

We investigate the dependence of the Yang-Mills wave functional in Coulomb gauge on the Faddeev-Popov determinant. We use a Gaussian wave functional multiplied by an arbitrary power of the Faddeev-Popov determinant. We show, that within the resummation of one-loop diagrams the stationary vacuum energy is independent of the power of the Faddeev-Popov determinant and, furthermore, the wave functi...

—This paper proposes a direct, and simple approach to the H∞ norm calculation in more general settings. In contrast to the method based on the Kalman–Yakubovich–Popov lemma, our approach does not require a controllability assumption, and returns a sinusoidal input that achieves the H∞ norm of the system including its frequency. In addition, using a semidefinite programming duality, we present a...

An important class of optimization problems in control and signal processing involves the constraint that a Popov function is nonnegative on the unit circle or the imaginary axis. Such a constraint is convex in the coefficients of the Popov function. It can be converted to a finitedimensional linear matrix inequality via the Kalman-Yakubovich-Popov lemma. However, the linear matrix inequality r...

In this paper we present a new approach to the Popov's Positivity Theorem and new statements and proofs of Absolute Stability Theorems. In the rst chapter we establish connexions between Riccati equations, Kalman-Yakubovitch-Popov systems and Luri e systems. We prove this results for stabilizable and antistabilizable solutions avoiding Youla's factorization. In the second chapter we state the A...

Eremostachys pulvinaris (family: Labiatae), one of the 60 species of the genus Eremostachys, occurs mainly in central Asian countries, e.g. Iran, Armenia, Ashgabad and the USSR. The rhizomes of this plant were collected from Tabriz in Azarbaijan province during September-October 2003. There is no report on any previous phytochemical investigation on E. pulvinaris available todate, phytochemical...

background and objectives: the aerial part extracts of eremostachys macrophylla  from labiatae family, which has been traditionally used in wound healing, snake bites, rheumatism and joint pains, were investigated for general toxicity, anti-proliferative, free radical scavenging and anti-bacterial effects.moreover, preliminary phytochemical investigations were carried out on the extracts. metho...

An important class of optimization problems in control and signal processing involves the constraint that a Popov function is nonnegative on the unit circle or the imaginary axis. Such a constraint is convex in the coefficients of the Popov function. It can be converted to a finitedimensional linear matrix inequality via the Kalman-Yakubovich-Popov lemma. However, the linear matrix inequality r...