  In this paper we face the study of the representations of the exceptional Lie
superalgebra E(5,10). We recall the construction of generalized Verma modules
and give a combinatorial description of the restriction to sl_5 of the Verma
module induced by the trivial representation. We use this description to
classify morphisms between Verma modules of degree one, two and three proving
in these cases a conjecture given by Rudakov. A key tool is the notion of dual
morphism between Verma modules.
