The general multi-dimensional Riemann problem for hyperbolic systems with real constant coefficients (Q1599890)

The authors give explicit solutions to the general multidimensional Riemann problem for the canonical form of hyperbolic systems of two equations in two space variables with real constant coefficients. I.e. they solve the Cauchy problem with initial data \(U_0(\theta)=(u_0(\theta)\), \(v_0(\theta)) \), where \(u_0,v_0\) are bounded, piecewise constant smooth functions of polar angle \(\theta\) on \(\langle 0,2\pi \rangle\).