TY - JOUR A1 - Möller, Bernhard A1 - Struth, Georg T1 - Algebras of modal operators and partial correctness T2 - Theoretical Computer Science N2 - Modal Kleene algebras are Kleene algebras enriched by forward and backward box and diamond operators. We formalise the symmetries of these operators as Galois connections, complemetarities and dualities. We study their properties in the associated operator algebras and show that the axioms of relation algebra are theorems at the operator level. Modal Kleene algebras provide a unifying semantics for various program calculi and enhances efficient cross-theory reasoning in this class, often in a very concise pointfree style. This claim is supported by novel algebraic soundness and completeness proofs for Hoare logic and by connecting this formalism with an algebraic decision procedure. Y1 - 2006 UR - https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/39151 UR - https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-391513 SN - 0304-3975 VL - 351 IS - 2 SP - 221 EP - 239 PB - Elsevier BV ER -