# What is the point of canonical form in PDEs?

I have been looking at canonical forms of second order PDEs:
http://www.math.psu.edu/wysocki/M412/Notes412_5.pdf

My question is: why is that useful? It doesn’t seem to make the PDEs any easier to solve.

A hyperbolic equation for example becomes(Copied from above link)
wξν+L[w]=Gw_{\xi\nu}+L[w]=G, where L is some first order operator and G some function.
That doesn’t seem much easier to solve than a hyperbolic equation to me.

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