Continuous coexistency preservers on effect algebras *

Abstract

Abstract Let H be a finite-dimensional Hilbert space, dim H ⩾ 2. We prove that every continuous coexistency preserving map on the effect algebra E(H) is either a standard automorphism of E(H), or a standard automorphism of E(H) composed with the orthocomplementation. We present examples showing the optimality of the result.