The Riemann problem for the planar motion of an elastic string
Michael Shearer · Journal of Differential Equations · 1986
where T= 7’( Ir,l) is the tension in the string, taken here to be a given smooth monotonically increasing function of the stretch 1~~~1 alone. In (l.l), we have also taken the density of the material of the string to be constant. The derivation of Eq. (1.1) (and of more general equations of motion for the string) is explained in [l]. In a previous paper [5], the Riemann problem was solved for system ( 1.1) under two assumptions: that the graph of T has exactly one inflection point, at t,, with