SAGBI bases for rings of formal modular seminvariants

We use the theory oi S.A.G.B.I, bases to construct a generating set for the ring of invariants for the four and live dimensional indecomposable modula r representations of a cyclic group of prime order. We observe that for the four dimensional representation the ring of invariants is generated in deg rees less than or equal to 2p - 3, and for the five dimensional representat ion the ring of invariants is generated in degrees less than or equal to 2p - 2.