Thanks for the suggestion, but I am already comfortable with Green's functions at that level; likewise, I am familiar with characteristics for wave-like PDEs . I believe Byron and Fuller mainly tackle typical second order linear PDEs like the wave equation, Schrödinger's equation, etc. Based on the table of contents, I don't think Byron and Fuller contain much (if any) discussion of systems of first order equations. I am also familiar with characteristics for solving a single first order linear and nonlinear PDEs, and have looked at a couple of treatments of systems with two independent variables. I am just not skilled or confident enough to try to derive the method for greater than two independent variables. I am interested in learning how to tackle problems that have, say, 6 equations, 6 dependent variables and 4 independent variables (x,y,z,t).
thanks,
jason