 Most examples of abstract CR structures are of hypersurface type.Suppose that "M" is a CR manifold of hypersurface type.The Levi form is the vector valued 2-form, defined on "L", with values in the line bundle

given by

"h" defines a sesquilinear form on "L" since it does not depend on how "v" and "w" are extended to sections of "L", by the integrability condition.