A remark on sums of squares of complex vector fields

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74609This note is a comment on a recent paper by J. J. Kohn. We give an example of a second order partial differential operator, expressed as a sum of squares of complex vector fields satisfying the bracket condition, that is not hypoelliptic.5 pagesComplex VariablesAnalysis of PDEs35H10; 32W10A remark on sums of squares of complex vector fieldstext