... semistable,and, being both of degree 0, the sheaf E1is also of degree 0 and Mumfordsemistable. Note that E1is a solvable ideal of E, i.e. the fibers of E1are solvableideals of the fibers of ... Section 1 the results in [G-S1] in orderto construct the moduli space of g-sheaves, then that of principal sheaves inSections 2, 3 and 4.Recall, from the introduction, the notion of a principal ... of Ei. After fixing the Chern classes of E and of the line bundles associated to the principal bundle P and characters of G, we obtain a projective moduli space of semistable principal G-sheaves.We...