S. Kharibegashvili
abstract:
For a class of first and second order hyperbolic systems with symmetric 
principal part, to which belong systems of Maxwell and Dirac equations, crystal 
optics equations, equations of the mathematical theory of elasticity and so on 
which are well known from the mathematical physics, we have developed a method 
allowing one to give correct formulations of boundary value problems in dihedral 
angles and conical domains in Sobolev spaces. For second order hyperbolic 
equations of various types of degeneration, we study the multidimensional 
versions of the Goursat and Darboux problems in dihedral angles and conical 
domains in the corresponding Sobolev spaces with weight. For the wave equation 
with one or two spatial variables, the correctness of some nonlocal problems is 
shown. The existence or nonexistence of global solutions of the characteristic 
Cauchy problem in a conic domain is studied for multidimensional wave equations 
with power nonlinearity.
Mathematics Subject Classification: 35L05, 35L20, 35L50, 35L70, 35L80, 35Q60
Key words and phrases: Hyperbolic equations and systems, hyperbolic systems with symmetric principal part, multidimensional versions of the Darboux and Goursat problems, degenerating hyperbolic equations of the second order, nonlocal problems, existence or nonexistence of global solutions for nonlinear wave equations