  For a finite cyclic p-group G and a discrete valuation domain R of
characteristic 0 with maximal ideal pR the R[G]-permutation modules are
characterized in terms of the vanishing of first degree cohomology on all sub-
groups (cf. Thm. A). As a consequence any R[G]-lattice can be presented by
R[G]-permutation modules (cf. Thm. C). The proof of these results is based on a
detailed analysis of the category of cohomological G-Mackey functors with
values in the category of R-modules. It is shown that this category has global
dimension 3 (cf. Thm. E). A crucial step in the proof of Theorem E is the fact
that a gentle R-order category (with parameter p) has global dimension less or
equal to 2 (cf. Thm. D).
