Programming in three-valued logic

AbstractThe aim of this paper is to propose a logical and algebraic theory which seems well-suited to logic programs with negation and deductive databases. This theory has similar properties to those of Prolog theory limited to programs with Horn clauses and thus can be considered as an extension of the usual theory. This parallel with logic programming without negation lies in the introduction of a third truth value (Indefinite) and of a new non-monotonic implication connective. Our proposition is different from the other ways of introducing a third truth value already used in Logic Programming and databases but it is somehow related to some of them, especially to Fitting's theory. We introduce a “consequence” operator associated with a logic program with negation which extends the operator of Apt and Van Emden. In the case of a consistent program, the post-fixpoints of this operator are the models of the program as they are usually. This operator is related to Fitting's one, the relation being obtained by completing the program. We finally give an operational semantics for a program with negation by the obtention of a three-valued interpreter from a bivalued one

A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV

Plasma wakefield acceleration (PWFA) holds much promise for advancing the energy frontier because it can potentially provide a 1000-fold or more increase in acceleration gradient with excellent power efficiency in respect with standard technologies. Most of the advances in beam-driven plasma wakefield acceleration were obtained by a UCLA/USC/SLAC collaboration working at the SLAC FFTB[ ]. These experiments have shown that plasmas can accelerate and focus both electron and positron high energy beams, and an accelerating gradient in excess of 50 GeV/m can be sustained in an 85 cm-long plasma. The FFTB experiments were essentially proof-of-principle experiments that showed the great potential of plasma accelerators. The FACET[ ] test facility at SLAC will in the period 2012-2016 further study several issues that are directly related to the applicability of PWFA to a high-energy collider, in particular two-beam acceleration where the witness beam experiences high beam loading (required for high efficiency), small energy spread and small emittance dilution (required to achieve luminosity). The PWFA-LC concept presented in this document is an attempt to find the best design that takes advantage of the PWFA, identify the critical parameters to be achieved and eventually the necessary R&D to address their feasibility. It best benefits from the extensive R&D that has been performed for conventional rf linear colliders during the last twenty years, especially ILC[ ] and CLIC[ ], with a potential for a comparably lower power consumption and cost.Comment: Submitted to the proceedings of the Snowmass Process CSS2013. Work supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF0051

Gamma-ray and radio tests of the e+e- excess from DM annihilations

PAMELA and ATIC recently reported an excess in e+e- cosmic rays. We show that if it is due to Dark Matter annihilations, the associated gamma-ray flux and the synchrotron emission produced by e+e- in the galactic magnetic field violate HESS and radio observations of the galactic center and HESS observations of dwarf Spheroidals, unless the DM density profile is significantly less steep than the benchmark NFW and Einasto profiles.Comment: 16 pages, 4 figures; v2: normalizations fixed in Table 2 and typos corrected (no changes in the analysis nor the results), some references and comments added; v3: minor additions, matches published versio

Exploring ultra-low β* values in ATF2 - R&D Programme proposal

We propose to explore the beam sizes and performance of the ATF2 Final Focus System for reduced IP beta functions up to a factor between 2 and 4 below its design. The results will demonstrate the feasibility of the system in a chromaticity regime of interest for CLIC and ILC

7th Drug hypersensitivity meeting: part two

No abstract availabl