Gevrey solvability and hypoellipticity of classes of partial differential operators
Solvability for a class of first order partial differential operators
Solvability and hypoellipticity of first order partial differential operators and...
Existence of periodic solutions for first-order partial differential equations
Solvability and hypoellipticity of first order partial differential operators and ...
Local solvability of rotationally invariant differential forms
Solvability for elliptic and canceling linear differential operators