35XX 


Partial differential equations 

35Gxx 

General higherorder equations and systems 


35G05 
General theory of linear higherorder PDE 


35G10 
Initial value problems for linear higherorder PDE, linear evolution equations 


35G15 
Boundary value problems for linear higherorder PDE 


35G20 
General theory of nonlinear higherorder PDE 


35G25 
Initial value problems for nonlinear higherorder PDE, nonlinear evolution equations 


35G30 
Boundary value problems for nonlinear higherorder PDE 


35G99 
None of the above, but in this section 