Memoization for Unary Logic Programming: Characterizing PTIME

We give a characterization of deterministic polynomial time computation based on an algebraic structure called the resolution semiring, whose elements can be understood as logic programs or sets of rewriting rules over first-order terms. More precisely, we study the restriction of this framework to terms (and logic programs, rewriting rules) using only unary symbols. We prove it is complete for polynomial time computation, using an encoding of pushdown automata. We then introduce an algebraic counterpart of the memoization technique in order to show its PTIME soundness. We finally relate our approach and complexity results to complexity of logic programming. As an application of our techniques, we show a PTIME-completeness result for a class of logic programming queries which use only unary function symbols.Comment: Soumis {\`a} LICS 201

Bank Employee Incentives and Stock Purchase Plans Participation

International audienceWe investigate which factors influence 44,649 employees' decision to invest in a top retail banking group in France. We have two objectives: (i) to explore factors associated with the amount invested in the plan, and (ii) to explore whether these factors have same associations with the probability of investing more than the incentive pay i.e. being an active investor. Specifically, we focus on four parameters that have been shown to affect participation: liquidity constraints, imperfect knowledge of the plan, asset choice, and transaction costs. We confirm Engelhardt and Madrian (Natl Tax J 57:385–406, 2004) assumptions according to which such factors contribute to explain non-participation. We show that ESPP contributors have very specific and unobserved motivations, as shown with the positive correlations between error terms in the two steps of investment decisions. The existence of unobservable investment motives can be explained by a lower risk aversion, a higher time preference, or a strong willingness to participate to corporate governance

Characterizing co-NL by a group action

International audienceIn a recent paper, Girard proposes to use his recent construction of a geometry of interaction in the hyperfinite factor in an innovative way to characterize complexity classes. We begin by giving a detailed explanation of both the choices and the motivations of Girard's definitions. We then provide a complete proof that the complexity class co-NL can be characterized using this new approach. We introduce as a technical tool the non-deterministic pointer machine, a concrete model to computes algorithms

Improving situation awareness of a single human operator interacting with multiple unmanned vehicles: first results

In the context of the supervision of one or several unmanned vehicles by a human operator, the design of an adapted user interface is a major challenge. Therefore, in the context of an existing experimental set up composed of a ground station and heterogeneous unmanned ground and air vehicles we aim at redesigning the human-robot interactions to improve the operator's situation awareness. We base our new design on a classical user centered approach

Comment on form factor shape and extraction of |V_ub| from B --> pi l nu

We point out that current experimental data for partial B --> pi l nu branching fractions reduce the theoretical input required for a precise extraction of |V_ub| to the form factor normalization at a single value of the pion energy. We show that the heavy-quark expansion provides a bound on the form factor shape that is orders of magnitude more stringent than conventional unitarity bounds. We find |V_ub| = (3.7 +/- 0.2 +/- 0.1) x [0.8/F_+(16 GeV^2)]. The first error is from the experimental branching fractions, and the second is a conservative bound on the residual form factor shape uncertainty, both of which will improve with additional data. Together with current and future lattice determinations of the form factor normalization this result gives an accurate, model independent determination of |V_ub|. We further extract semileptonic shape observables such as |V_ub F_+(0)| = 0.92 +/- 0.11 +/- 0.03 and show how these observables can be used to test factorization and to determine low-energy parameters in hadronic B decays.Comment: 14 pages, 3 figures; journal version, results and conclusions unchange

Probing photon helicity in radiative B decays via charmonium resonance interference

We investigate a new method to probe the helicity of the photon emitted in the b -> s gamma transition. The method relies on the observation of interference effects between two resonance contributions, B -> K*(K gamma) gamma and B -> eta_c(gamma gamma) K or B -> chi_c0(gamma gamma) K to the same final state K gamma gamma. Decays of the type B -> K_res(K gamma) gamma dominate the B -> K gamma gamma yield throughout most of the phase space, and may be accessible at current B meson facilities already.Comment: elsart, 11 pages, 4 figures; added comments on strong phase (final version Phys. Lett. B

Instrumental genesis through interdisciplinary collaboration -- reflections on the emergence of a visualisation framework for video annotation data

Instrumental genesis through interdisciplinary collaboration-reflections on the emergence of a visualisation framework for video annotation data XML This paper presents, discusses and reflects on the development of a visualization framework for the analysis of the temporal dynamics of audiovisual expressivity. The main focus lies on the instrumental genesis process (Rabardel 1995; Longchamp 2012)-a concept trying to express and analyze the co-evolution of instruments and the practices they make possible-underlying this development. It is described through the collaboration and communication processes between computer science scholars and humanities scholars in finding new ways of visualizing complex datasets for exploration and presentation in the realm of film-studies research. It draws on the outcome and concrete usage of the visualizations in publications and presentations of a research group, the AdAproject, that investigates the audiovisual rhetorics of affect in audiovisual media on the financial crisis (2007-). These film analyses are based on theoretical assumptions on the process of film-viewing, the relation of the viewer's perception and the temporally unfolding audiovisual images, and a methodical approach that draws on 'steps' in the research process such as segmentation, description and qualification, called eMAEX (Kappelhoff et al. 2011-2016) to reconstruct these experiential figurations (Bakels et al. 2020a, 2020b). The main focus of this paper is the process of iterative development of visualizations as interactive interfaces generated with the open-source software Advene, that were an integral part of the research process. In this regard, the timeline visualization is not only of interest for visual argumentation in (digital) humanities publications, but also for the creation of annotations as well as the exploration of this data. In the first part of the paper we describe this interdisciplinary collaboration as instrumental genesis on a general level-as an evolving and iterative process. In the second part we focus on the specific challenge of designing a visualization framework for the temporal dynamics of audiovisual aesthetics. Lastly we zoom out by reflecting on experiences and insights that might be of interest for the wider digital humanities community

Generalized Parton Distributions and Transversity in Nucleons and Nuclei

We present an exploratory study using generalized parton distributions of several observables related to transverse degrees of freedom in hadronic structure -- the nucleon transverse momentum, the transverse radius, or impact parameter, and the momentum transfer, $t$, dependence of the longitudinal variable $x$ -- in both nucleons and nuclei.Comment: 6 pages, 3 figures, Talk presented at "Baryons 04", October 25th-30th, 2004, Palaiseau, Franc

Progress in Understanding the Nuclear Equation of State at the Quark Level

At the present time there is a lively debate within the nuclear community concerning the relevance of quark degrees of freedom in understanding nuclear structure. We outline the key issues and review the impressive progress made recently within the framework of the quark-meson coupling model. In particular, we explain in quite general terms how the modification of the internal structure of hadrons in-medium leads naturally to three- and four-body forces, or equivalently, to density dependent effective interactions.Comment: Invited presentation at XXX Symposium on Nuclear Physics, Hacienda Cocoyoc, Jan. 3-6, 200