%0 Journal Article 
%A Moreno Frías, María Ángeles
%T Ext groups of Janet systems
%D 2003
%@ 0022-4049
%U http://hdl.handle.net/10498/35349
%X In this paper we develop the basic ideas of Janet by using the theory of D-modules. For the
so-called completely integrable systems (Janet Systems), we show that the higher Ext groups
are null
%K D-modules
%K completely integrable system
%K Differential Operators
%~ Universidad de Cádiz