
The paper presents two new proofs of the unsolvability of certain partial differential equations of first order \(Lf=g\). Both proofs depend on the theory of holomorphic functions of several complex variables. In the first case the unsolvability of \(Lf=g\) results from the existence of peak points in the topological algebra that is the kernel of \(L\). The proof yields a removable singularities theorem for \(L\). The second proof depends on the extension property of Hartogs type. [See H. Lewy, Ann. Math. (2) 64, 514--522 (1956; Zbl 0074.06204).]
General theory of partial differential operators, 32D99, 35A07, Linear first-order PDEs, Geometric convexity in several complex variables, 32F40
General theory of partial differential operators, 32D99, 35A07, Linear first-order PDEs, Geometric convexity in several complex variables, 32F40
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