Compositional Algorithms for Succinct Safety Games

We study the synthesis of circuits for succinct safety specifications given in the AIG format. We show how AIG safety specifications can be decomposed automatically into sub specifications. Then we propose symbolic compositional algorithms to solve the synthesis problem compositionally starting for the sub-specifications. We have evaluated the compositional algorithms on a set of benchmarks including those proposed for the first synthesis competition organised in 2014 by the Synthesis Workshop affiliated to the CAV conference. We show that a large number of benchmarks can be decomposed automatically and solved more efficiently with the compositional algorithms that we propose in this paper.Comment: In Proceedings SYNT 2015, arXiv:1602.0078

Aligned electric and magnetic Weyl fields

We analyze the spacetimes admitting a direction for which the relative electric and magnetic Weyl fields are aligned. We give an invariant characterization of these metrics and study the properties of its Debever null vectors. The directions 'observing' aligned electric and magnetic Weyl fields are obtained for every Petrov type. The results on the no existence of purely magnetic solutions are extended to the wider class having homothetic electric and magnetic Weyl fields.Comment: 14 page

Effect of electropolymerisation conditions on the permeability of polyphenol films deposited on a vitreous carbon electrode

Polymeric films were prepared from alkaline (NaOH) phenol aqueous solutions on a vitreous carbon (VC) electrode by potentiostatic or galvanostatic electro-oxidation. Permeation through such films was studied by rotating-disk electrode using the ferricyanide redox couple, and by cyclic voltammetry using phenate ions. The influence of the electropolymerisation controllable parameters such as NaOH and phenol concentrations, potential or current applied, electrosynthesis time, temperature and hydrodynamic conditions (electrode rotation + solution magnetic stirring) on the permeability of these polymeric films was examined. Conditions for the removal of phenol by electropolymerisation are discussed on the basis of the permeability of polyphenol films obtained by electrosynthesis. Permeable films were formed for a concentration of free hydroxyl anion larger of 0.1 M. An increase of the temperature to 85°C favours the formation of highly permeable films, thus avoiding electrode fouling

Coreference-Based Summarization and Question Answering: a Case for High Precision Anaphor Resolution

Approaches to Text Summarization and Question Answering are known to benefit from the availability of coreference information. Based on an analysis of its contributions, a more detailed look at coreference processing for these applications will be proposed: it should be considered as a task of anaphor resolution rather than coreference resolution. It will be further argued that high precision approaches to anaphor resolution optimally match the specific requirements. Three such approaches will be described and empirically evaluated, and the implications for Text Summarization and Question Answering will be discussed