This volume features selected papers from The Fifteenth International Conference on Order Analysis and Related Problems of Mathematical Modeling, which was held in Vladikavkaz, Russia, on 15 - 20th July 2019. Intended for mathematicians specializing in operator theory, functional spaces, differential equations or mathematical modeling, the book provides a state-of-the-art account of various fascinating areas of operator theory, ranging from various classes of operators (positive operators, convolution operators, backward shift operators, singular and fractional integral operators, partial differential operators) to important applications in differential equations, inverse problems, approximation theory, metric theory of surfaces, the Hubbard model, social stratification models, and viscid incompressible fluids.

Inhalt
Extinction In a Finite Time for Parabolic Equations of Fast Diffusion Type on Manifolds.- Inverse Problems In The Multidimensional Hyperbolic Equation With Rapidly Oscillating Absolute Term.- On The Brezis-Lieb Lemma and Its Extensions.- On the Commutant of the Generalized Backward Shift Operator in Weighted Spaces of Entire Functions.- The Conditions of Global Boundedness for the Solutions of Continuous Social Stratification Model.- Stochastic Test of a Minimal Surface.- On Isomorphism of Some Functional Spaces under Action of Two Dimensional Singular Integral Operators.- On One Class of Solutions of The Darboux System.- Boolean Valued Analysis: Background And Results.- Approximation Properties of Vallee Poussin Means For Special Series of Ultraspherical Jacobi.- Laplace's Integrals And Stability of The Open Flows of in Viscid Incompressible Fluid.- Spectral Properties of Killing Vector Fields of Constant Length And Bounded Killing Vector Fields.- The Radon-Nikodym Theorem for Disjointness ´Preserving Orthogonally Additive Operators.- On Continuous Linear Right Inverse To Convolution Operator.- Long Wavelength Asymptotics of Self-Oscillations of Viscous Incompressible Fluid.- The convergence of the Fourier Jacobi series in weighted variable exponent Lebesgue spaces.- Hyperbolic B-potentials: Properties and Inversion.- Some Properties of Sobolev Orthogonal Polynomials Associated with Chebyshev Polynomials of the Second Kind.- Structure of Essential Spectrum and Discrete Spectra of The Energy Operator of Five-Electron Systems In The Hubbard Model. Doublet States.- On Coefficient Inverse Problems of Heat Conduction for Functionally Graded Materials.- Investigation Of Waves Processes In Inhomogeneous Cylindrical Waveguides.- Solution Of Some Class First-Order Quasilinear Partial Differential Equations.