We consider a class of involutive systems of n smooth vector fields on the n + 1 dimensional torus. We obtain a complete characterization for the global solvability of this class in terms of Liouville forms and of the ...

This paper deals with semi-global C(k)-solvability of complex vector fields of the form L = partial derivative/partial derivative t + x(r) (a(x) + ib(x))partial derivative/partial derivative x, r >= 1, defined on Omega(epsilon) ...

The goal of this paper is study the global solvability of a class of complex vector fields of the special form L = partial derivative/partial derivative t + (a + ib)(x)partial derivative/partial derivative x, a, b epsilon ...

This work deals with global solvability and global hypoellipticity of complex vector fields of the form L = ∂/∂t + i 'B IND. 1 '(t)∂/∂ 'X IND. 1' + i 'B IND. 2' (t)∂/∂ 'X IND. 2', defined on 'T POT. 3' _~ 'R POT. 3'/2 ...

This paper deals with the solvability near the characteristic set Σ = {0}× 'S POT.1' of operators of the form L = ∂/∂t+('X POT.N'a(x)+ixb(x))∂/∂x, b(0) 'DIFERENTE DE' 0 and n ≥ 2, defined on 'Ω IND.E' = (−E, E) × 'S POT.1', ...

We give a short and geometric proof, based on Jacobi fields, of a theorem of K. Abe that asserts that the relative index of nullity is trivial for complete non-totally geodesic complex projective submanifolds. Using this ...

We consider real analytic involutive structures V, of co-rank one, defined on a real analytic paracompact orientable manifold M. To each such structure we associate certain connected subsets of M which we call the level ...