An invariant for modules over a discrete valuation ring
An invariant for modules over a discrete valuation ring
Warfield has recently defined a new class of invariants for mixed modules over a discrete valuation ring. These invariants, along with the Ulm invariants, enable Warfield to prove an analogue to Ulm’s theorem. Warfield’s definition contains two shortcomings. The invariants are defined for a limited class of modules. Moreover it …