35Lxx Partial differential equations of hyperbolic type

35L05  Wave equation
35L10  General theory of second-order, hyperbolic equations
35L15  Initial value problems for second-order, hyperbolic
               equations
35L20  Boundary value problems for second-order, hyperbolic
               equations
35L25  General theory of higher-order, hyperbolic equations
35L30  Initial value problems for higher-order, hyperbolic
               equations
35L35  Boundary value problems for higher-order, hyperbolic
               equations
35L40  General theory of hyperbolic systems of first-order PDE
35L45  Initial value problems for hyperbolic systems of
               first-order PDE
35L50  Boundary value problems for hyperbolic systems of
               first-order PDE
35L55  Hyperbolic systems of higher-order PDE
35L60  Nonlinear first-order PDE of hyperbolic type
35L65  Conservation laws
35L67  Shocks and singularities, See also {58C27, 76L05}
35L70  Nonlinear second-order PDE of hyperbolic type
35L75  Nonlinear hyperabolic PDE of higher ($\gtr 2$) order
35L80  Hyperbolic PDE of degenerate type
35L85  Unilateral problems; variational inequalities for
               hyperbolic PDE, See also {35R35, 49J40}
35L99  None of the above but in this section