34,451 research outputs found

    The silence of self-knowledge

    Get PDF
    Gareth Evans famously affirmed an explanatory connection between answering the question whether p and knowing whether one believes that p. This is commonly interpreted in terms of the idea that judging that p constitutes an adequate basis for the belief that one believes that p. This paper formulates and defends an alternative, more modest interpretation, which develops from the suggestion that one can know that one believes that p in judging that p

    Six-Dimensional Supergravity on S^3 X AdS_3 and 2d Conformal Field Theory

    Get PDF
    In this paper we study the relation between six-dimensional supergravity compactified on S^3 X AdS_3 and certain two-dimensional conformal field theories. We compute the Kaluza-Klein spectrum of supergravity using representation theory; these methods are quite general and can also be applied to other compactifications involving anti-de Sitter spaces. A detailed comparison between the spectrum of the two-dimensional conformal field theory and supergravity is made, and we find complete agreement. This applies even at the level of certain non-chiral primaries, and we propose a resolution to the puzzle of the missing states recently raised by Vafa. As a further illustration of the method the Kaluza-Klein spectra of F-theory on M^6 X S^3 X AdS_3 and of M-theory on M^6 X S^2 X AdS_3 are computed, with M^6 some Calabi-Yau manifold.Comment: 32 pages, LaTeX; minor corrections, reference adde

    Sterile Neutrino as a Bulk Neutrino

    Get PDF
    If light sterile neutrinos are needed to understand the neutrino puzzles, as is currently indicated, a major theoretical challenge is to understand why its mass is so small. It is a more serious problem than understanding the small mass of the familiar neutrinos. We discuss a new way to solve this problem by identifying the sterile neutrino as gauge neutral fermion propagating in the bulk of a higher dimensional theory, with bulk size of order of a millimeter. The smallness of its mass is then a consequence of the size of the extra dimension and does not need the introduction of new symmetries. We present a realistic model for neutrino masses and mixings that implements this idea.Comment: 13 pages, no figures; minor typos correcte

    The consumption-tightness puzzle

    Get PDF
    This paper introduces a labor force participation choice into a labor market matching model embedded in a dynamic stochastic general equilibrium set-up with production and savings. The participation choice is modelled as a tradeoff between forgoing the expected benefits of being search active and engaging in costly labor market search. The model induces a symmetry in firms’ and workers’ search decision since both sides of the labor market vary search effort at the extensive margins. We show that this set-up is of considerable analytical convenience and that it gives rise to a linear relationship between labor market tightness and the marginal utility of consumption. We refer to the latter as the “consumption - tightness puzzle” because (a) it gives rise to a number of counterfactual implications, and (b) it is a robust implication of theory. Amongst the counterfactual implications are very low volatility of tightness, procyclical unemployment, and a positively sloped Beveridge curve. These implications all derive from procyclical variations in participation rates that follow from allowing for the extensive search margin

    The mixing time of the fifteen puzzle

    Full text link
    We show that there are universal positive constants c and C such that the mixing time T_{mix} for the fifteen puzzle in an n by n torus satisfies cn^4 log n < T_{mix} < Cn^4 log^2 n.Comment: 30 pages, 9 figure

    Trains, Games, and Complexity: 0/1/2-Player Motion Planning through Input/Output Gadgets

    Full text link
    We analyze the computational complexity of motion planning through local "input/output" gadgets with separate entrances and exits, and a subset of allowed traversals from entrances to exits, each of which changes the state of the gadget and thereby the allowed traversals. We study such gadgets in the 0-, 1-, and 2-player settings, in particular extending past motion-planning-through-gadgets work to 0-player games for the first time, by considering "branchless" connections between gadgets that route every gadget's exit to a unique gadget's entrance. Our complexity results include containment in L, NL, P, NP, and PSPACE; as well as hardness for NL, P, NP, and PSPACE. We apply these results to show PSPACE-completeness for certain mechanics in Factorio, [the Sequence], and a restricted version of Trainyard, improving prior results. This work strengthens prior results on switching graphs and reachability switching games.Comment: 37 pages, 36 figure
    • 

    corecore