Proceedings of the Fourth International Colloquium on Differential Equations, Plovdiv, Bulgaria, 18–22 August 1993

Frontmatter -- CONTENTS -- Preface -- Periodic solutions for multi-phase Stefan problems with dynamic boundary conditions -- Overdetermined Problems for Elliptic Equations -- Mixed Finite-Element Methods for the Equations of Flow in Porous Media -- Limit sets of impulsive dynamical systems -- Non-classical dynamic programming in optimal control -- Painleve analysis of nonlinear reaction-diffusion -- Weighted interpolation and Hardy inequalities with some spectral theoretic applications -- Relativity and Gravitation: Probabilistic Germs and Survey -- Monodromic Unbounded Polycycles -- Uniform Schemes for Singularly Perturbed Scalar Initial Value Problems -- The Operator Theoretical Treatment of Partial Differential Equations: Recent Developments with Applications -- Hilbert-Arnold problem for cubic Hamiltonians and limit cycles -- Periodic solutions of neutral impulsive systems with a small delay -- Analytic-numerical solutions of variable coefficient second order delay differential equations -- Localization of Global Existence of Holomorphic Solutions of Differential Equations with Complex Parameters -- Conditions for the Absence of Positive Solutions of First Order Differential Inequalities with Deviating Arguments -- On the solution of boundary value problem. The decomposition method -- Some uniform estimates for solutions of difference differential equations of elliptic-parabolic type -- The Eigenvalue Distribution of Elliptic Operators with Holder Continuous Coefficients -- Applications of an adaptive finite element method -- Formation of Shocks for Nonlinear Partial Differential Equations of First Order -- On some degenerate nonlinear parabolic equations -- Existence Theory for Singular Two Point Boundary Value Problems -- Microlocal hypoellipticity of some classes of overdetermined systems of pseudodifferential operators -- A Two Point Connection Problem For A Certain Third Order Differential Equation -- Strong-electric-field eigenvalue asymptotics for the perturbed magnetic Schrodinger operator -- Stability Theory for a Class of 2D Linear Systems Described by a Set of Recursive Differential Equations -- Analyticity of the Solutions of the Heat Equation on the Half Space Rn+ -- Recent Advances in the Method of Quasilinearization -- On a radially symmetric minimal surface with non-empty free boundary -- Sampling Theorems Associated with Boundary-Value Problems