A recursive basis for primitive forms in symplectic spaces and applications to Heisenberg groups

This paper is divided in two parts: in Section 2, we define recursively a privileged basis of the primitive forms in a symplectic space (V 2n, .). Successively, in Section 3, we apply our construction in the setting of Heisenberg groups .n, n . 1, to write in coordinates the exterior differential of the so-called Rumin.s complex of differential forms in .n.