The observations of the solar F-corona from space are reviewed emphasizing 25 years continuous monitoring achieved by LASCO-C2 and C3 coronagraphs. Our work includes images obtained Clementine cameras, STEREO/SECCHI/HI-1A PSP/WISPR heliospheric imagers. characteristic radiance profiles along equatorial polar directions follow power laws in 5{\deg}-50{\deg} range elongation, with constant expone...

To clear up both algebraic and geometric structures for integrable systems derived from selfconsistent field theory, in particular, geometric aspect of the random-phase-approximation (RPA) equation is exhibited on the basis of the viewpoint of symmetry of the evolution equation. The RPA equation for an infinite-dimensional Grassmannian is constructed. c © 2002 MAIK “Nauka/Interperiodica”.

This paper studies, with techniques of Abstract Algebraic Logic, the effects of putting a bound on the cardinality of the set of side formulas in the Deduction Theorem, viewed as a Gentzen-style rule, and of adding additional assumptions inside the formulas present in Modus Ponens, viewed as a Hilbert-style rule. As a result, a denumerable collection of new Gentzen systems and two new sententia...

Matrix spectral factorization is traditionally described as finding spectral factors having a fixed analytic pole configuration. The classification of spectral factors then involves studying the solutions of a certain algebraic Riccati equation which parametrizes their zero structure. The pole structure of the spectral factors can be also parametrized in terms of solutions of another Riccati eq...

In this paper, we study the Chebyshev centres of bounded subsets of normed spaces and obtain a norm inequality for relative centres. In particular, we prove that if T is a remotal subset of an inner product space H, and F is a star-shaped set at a relative Chebyshev centre c of T with respect to F, then llx - qT (x)1I2 2 Ilx-cll2 + Ilc-qT (c) 112 x E F, where qT : F + T is any choice functi...