Address.
Departamento de Matematicas,
Universidad de Salamanca, Plaza de la Merced 1-4, E-37008 Salamanca,
Spain
E-mail. ricardo@usal.es
Abstract.
Jets of a manifold $M$ can be described as ideals of
$\C^\infty(M)$. This way, all the usual processes on jets
can be directly referred to that ring.
By using this fact, we give a very simple construction of
the contact system on jet spaces.
The same way, we also define the contact system for
the recently considered $A$-jet spaces, where $A$ is a Weil
algebra. We will need to introduce the concept
of \emph{derived algebra}.
AMSclassification. 58A20.
Keywords. Jet, contact system, Weil algebra, Weil bundle.