This is the first of two Euroconferences aimed at addressing the issues of Nonlinearity and Disorder. The 1995 Euroconference was devoted to the mathematical, numerical and experimental studies related to the Klein-Gordon and Schrödinger systems. The Euroconference was organized around main lectures in each area to introduce the main concepts and stimulate discussions. The mathematical studies covered the functional anlaysis and stochastic techniques applied to the general Klein-Gordon and Schrödinger wave equations. Also a panoramic view of the numerical schemes was presented to simulate the above equations, as well as an overview of the applications of such systems in the areas of condensed matter, optical physics, new materials and biophysics. Special attention was devoted to the discrete Schrödinger and Klein-Gordon systems and their applications.

The book details a few of the novel methods developed in the last few years for studying various aspects of nonlinear wave systems. The introductory chapter provides a general overview, thematically linking the objects described in the book. Two chapters are devoted to wave systems possessing resonances with linear frequencies (Chapter 2) and with nonlinear frequencies (Chapter 3). In the next two chapters modulation instability in the KdV-type of equations is studied using rigorous mathematical methods (Chapter 4) and its possible connection to freak waves is investigated (Chapter 5). The book goes on to demonstrate how the choice of the Hamiltonian (Chapter 6) or the Lagrangian (Chapter 7) framework allows us to gain a deeper insight into the properties of a specific wave system. The final chapter discusses problems encountered when attempting to verify the theoretical predictions using numerical or laboratory experiments. All the chapters are illustrated by ample constructive examples demonstrating the applicability of these novel methods and approaches to a wide class of evolutionary dispersive PDEs, e.g. equations from Benjamin-Oro, Boussinesq, Hasegawa-Mima, KdV-type, Klein-Gordon, NLS-type, Serre, Shamel , Whitham and Zakharov. This makes the book interesting for professionals in the fields of nonlinear physics, applied mathematics and fluid mechanics as well as students who are studying these subjects. The book can also be used as a basis for a one-semester lecture course in applied mathematics or mathematical physics.

Pt. I. Analytical methods. On the IST for discrete nonlinear Schrödinger systems and polarization shift for discrete vector solitons / M.J. Ablowitz, B. Prinari, A.D. Trubatch -- Soliton solutions of coupled nonlinear Klein-Gordon equations / T. Alagesan -- Characteristic initial value problems for integrable hyperbolic reductions of Einstein's equations / G.A. Alekseev -- Discrete sine-Gordon equation / M. Boiti [und weitere] -- Integrable and non-integrable equations with peakons / A. Degasperis, D.D. Holm, A.N.W. Hone -- Solution of a free boundary problem for a nonlinear diffusion-convection equation / S. De Lillo, M.C. Salvatori, G. Sanchini -- Iterative construction of solutions for a nonisospectral problem in 2 + 1 dimensions / P.G. Estevez -- Discrete breathers close to the anticontinuum limit: existence and wave scattering / S. Flach [und weitere] -- Complex Toda chain - an integrable universal model for adiabatic N-soliton interactions! / V.S. Gerdjikov -- On the reductions and scattering data for the generalized Zakharov-Shabat systems / G.G. Grahovski -- Bilinear representation for the modified nonlinear Schrödinger equations and their quantum potential deformations / J.H. Lee, O.K. Pashaev -- Noncommutative Burgers' equations / L. Martina, O.K. Pashaev -- On the quasi-classical [sumbol]-dressing method / B. Konopelchenko, A. Moro -- New solvable matrix integrals - U(n) case / A. Yu. Orlov -- Integrable hydrodynamic chains / M.V. Pavlov -- KPII: new results and open problems / A.K. Pogrebkov -- A workmate for KdV / P.C. Sabatier -- Space-time lattice for operator Schrödinger equation / A. Spire, V.V. Konotop, L. Vazquez -- On isomonodromy deformations for the ZS-AKNS flows / D. Wu -- pt. II. Symmetry properties, Hamiltonian methods and group theoretical methods. New symmetry reductions for a lubrication model / M.S. Bruzón [und weitere] -- Quantum solitons for quantum information and quantum computing / R.K. Bullough, M. Wadati -- Solving renormalization group equations by recursion relations / A. Cafarella, C. Corianò, M. Guzzi -- A tri-Hamiltonian route to spectral curves / L. Degiovanni, G. Magnano -- Construction of real forms of complexified Hamiltonian dynamical systems / V.S. Gerdjikov [und weitere] -- Integrable and super-integrable systems in classical and quantum mechanics / M. Giordano [und weitere] -- Non-commuting coordinates in vortex dynamics and in the Hall effect, related to "exotic" Galilean symmetry / P.A. Horváthy -- Structure of multi-meron knot action / L.S. Isaev, A.P. Protogenov -- Compatible nonlocal Poisson brackets of hydrodynamic type and integrable reductions of the Lamé equations / O.I. Mokhov -- Pseudoanti-Hermiticity in QQM, time-reversal and Kramers degeneracy / G. Scolarici -- On the integrability of supersymmetric equations / P. Tempesta, R.A. Leo, G. Soliani

This scientific book was written for specialists on the theory and application of numerical approximation techniques, primarily for mathematicians, scientists, and engineers. The book outlines numerical methods and their applications for systems of linear and nonlinear equations, interpolation, numerical integration and solving problems with differential equations, partial differential equations or fractional differential equations. It explores techniques in C++, Maple, and MATLAB, develops mathematical methods through computation and develops numerical methods in the context of case studies for data analysis, optimisation, linear algebra and differential equations.