A SURVEY ON SHARP ELEMENTS IN UNSHARP QUANTUM LOGICS

Gejza Jenča - Zdenka Riečanová

   In 1999, Moreland and Gudder noted that there are two main types of effects, the sharp effects which describe perfectly accurate yes-no measurements and the unsharp effects which describe yes-no measurements that are imprecise. However, the set of all sharp elements of an effect algebra E need not be a sub-effect algebra of E nor an orthomodular lattice or poset. In this survey paper we present some classes of effect algebras in which sharp elements form sub-effect algebras that are in some cases even orthomodular lattices or

Keywords: effect algebra, MV-algebra, sharp elements, orthomodular lattice

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