[isabelle] Two new AFP entries



A shallow embedding of HyperCTL*

by Markus N. Rabe, Peter Lammich and Andrei Popescu

We formalize HyperCTL*, a temporal logic for expressing security properties. We first define a shallow embedding of HyperCTL*, within which we prove inductive and coinductive rules for the operators. Then we show that a HyperCTL* formula captures Goguen-Meseguer noninterference, a landmark information flow property. We also define a deep embedding and connect it to the shallow embedding by a denotational semantics, for which we prove sanity w.r.t. dependence on the free variables. Finally, we show that under some finiteness assumptions about the model, noninterference is given by a (finitary) syntactic formula.

http://afp.sourceforge.net/entries/HyperCTL.shtml


Abstract Completeness

by Jasmin Christian Blanchette, Andrei Popescu and Dmitriy Traytel

A formalization of an abstract property of possibly infinite derivation trees (modeled by a codatatype), representing the core of a proof (in Beth/Hintikka style) of the first-order logic completeness theorem, independent of the concrete syntax or inference rules. This work is described in detail in the IJCAR 2014 publication by the authors. The abstract proof can be instantiated for a wide range of Gentzen and tableau systems as well as various flavors of FOL---e.g., with or without predicates, equality, or sorts. Here, we give only a toy example instantiation with classical propositional logic. A more serious instance---many-sorted FOL with equality---is described elsewhere [Blanchette and Popescu, FroCoS 2013].

http://afp.sourceforge.net/entries/Abstract_Completeness.shtml

Contributions are coming in thick and fast these days.

Larry Paulson






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