Solvability of a first order linear partial differential equation

Linear Partial Differential Operators

1963 • 2,444 citations

An Example of a Smooth Linear Partial Differential Equation Without Solution

1957 • 254 citations

Solutions nulles et solutions non analytiques

1962 • 92 citations

Differential equations without solutions

1960 • 73 citations

A Complex Frobenius Theorem

2011 • 63 citations

Differential operators of principal type

1960 • 61 citations