User:Differentialpi/Riemann problem/Comments

Community, This article, as of Oct 2015, has several issues that make it confusing to the reader trying to learn about the Riemann problem for the first time. I am not an expert on the problem now to know the best approach to correct this issues, but I'll list them here.
 * ρo is never defined.
 * a is never formally defined. Since this page uses fluid flow as the simple example, a represents the sound speed. Why not define it as such and then suggest how it can be generalized for other problems (e.g., speed of the characteristics)?
 * The key step in solving the Riemann problem comes near the end where the interior region U* is written as a special linear combination of the eigenbasis elements. Why those particular coefficients? Said another way, why is that particular linear combination what we need?

Differentialpi (talk) 19:43, 9 October 2015 (UTC)