A few splitting theorems for rank two vector bundles on P^4

The paper investigates vanishing conditions on the intermediate cohomology of a normalized rank $2$ vector bundle $\F$ on $\P^4$ which force $\F$ to split or, at least, to be a non-stable bundle (with few possible exceptions). The results are applied to see when subcanonical surfaces on $\P^4$ are forced to be complete intersections of two hypersurfaces, since subcanonical surfaces are zero loci of non-zero sections of rank $2$ vector bundles