Extend sequential transversality beyond strictly hyperbolic genuinely nonlinear systems
Extend the sequential-transversality framework to hyperbolic conservation-law regimes that violate genuine nonlinearity or strict hyperbolicity, including composite waves, contact discontinuities, coinciding or crossing characteristic speeds, and the corresponding adapted admissibility criteria.
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Several directions remain open. Our analysis operates under Assumptions~\ref{ass:SH} (strict hyperbolicity) and~\ref{ass:GN} (genuine nonlinearity), which together restrict attention to classical Lax shocks and rarefactions and exclude composite waves and contact discontinuities. Relaxing Assumption~\ref{ass:GN} admits strictly hyperbolic systems with non-convex flux, such as the van der Waals $p$-system in the supercritical regime, whose inflection points generate composite waves, while relaxing Assumption~\ref{ass:SH} opens the door to systems with coinciding or crossing characteristic speeds. Extending the sequential-transversality framework to these regimes, with admissibility criteria adapted to each wave type, is a natural next step.