24,901 research outputs found

    A renormalisation group method. II. Approximation by local polynomials

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    This paper is the second in a series devoted to the development of a rigorous renormalisation group method for lattice field theories involving boson fields, fermion fields, or both. The method is set within a normed algebra N\mathcal{N} of functionals of the fields. In this paper, we develop a general method---localisation---to approximate an element of N\mathcal{N} by a local polynomial in the fields. From the point of view of the renormalisation group, the construction of the local polynomial corresponding to FF in N\mathcal{N} amounts to the extraction of the relevant and marginal parts of FF. We prove estimates relating FF and its corresponding local polynomial, in terms of the TÏ•T_{\phi} semi-norm introduced in part I of the series.Comment: 30 page

    A renormalisation group method. IV. Stability analysis

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    This paper is the fourth in a series devoted to the development of a rigorous renormalisation group method for lattice field theories involving boson fields, fermion fields, or both. The third paper in the series presents a perturbative analysis of a supersymmetric field theory which represents the continuous-time weakly self-avoiding walk on Zd\mathbb{Z}^d. We now present an analysis of the relevant interaction functional of the supersymmetric field theory, which permits a nonperturbative analysis to be carried out in the critical dimension d=4d = 4. The results in this paper include: proof of stability of the interaction, estimates which enable control of Gaussian expectations involving both boson and fermion fields, estimates which bound the errors in the perturbative analysis, and a crucial contraction estimate to handle irrelevant directions in the flow of the renormalisation group. These results are essential for the analysis of the general renormalisation group step in the fifth paper in the series.Comment: 62 page

    Facilitating open plot structures in story driven video games using situation generation

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    Story driven video games are rising in popularity, along with the players desire to make meaningful choice within the plot and therefore become more involved and immersed within the experience. This paper investigates the problems which arise from implementing interactive narrative within video games and potential techniques to solve those problems. The main focus of the study was the situation generation technique, used to maintain the continuity within open, emergent plot structures, using behaviour trees as a means to implement and traverse plot sequences. The ISGEngine was developed during the course of this study in order to implement and evaluate the situation generation technique

    Libet and Freedom in a Mind-Haunted World

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    Saigle, Dubljevic, and Racine (2018) claim that Libet-style experiments are insufficient to challenge that agents have free will. They support this with evidence from experimen- tal psychology that the folk concept of freedom is consis- tent with monism, that our minds are identical to our brains. However, recent literature suggests that evidence from experimental psychology is less than determinate in this regard, and that folk intuitions are too unrefined as to provide guidance on metaphysical issues like monism. In light of this, it is worthwhile to examine the authors’ insuf- ficiency claim under the assumption that monism is false and dualism true (our minds are not identical to our brains). We conclude that, were dualism true, then Libet- style experiments would tell us no more about freedom and moral responsibility than what the authors initially claimed, thus further bolstering their point that Libet-style experiments are ill-suited to speak to the free will of agents. In what follows we first discuss some of the reasons to be skeptical of using folk intuitions to make claims about the nature of freedom and moral responsibility. We then draw from the work of E. J. Lowe to demonstrate that Libet-style experiments would likely give the same results regardless of the truth of monism or dualism

    Family Violence and Football: The Effect of Unexpected Emotional Cues on Violent Behavior

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    Family violence is a pervasive and costly problem, yet there is no consensus on how to interpret the phenomenon of violence by one family member against another. Some analysts assume that violence has an instrumental role in intra-family incentives. Others argue that violent episodes represent a loss of control that the offender immediately regrets. In this paper we specify and test a behavioral model of the latter form in which the strength of an emotional cue depends on outcomes relative to expectations and individuals exhibit loss aversion. Our key hypothesis is that negative emotional cues -- benchmarked relative to a rationally expected reference point -- make a breakdown of control more likely. We test this hypothesis using data on police reports of family violence on Sundays during the professional football season. Controlling for location and time fixed effects, weather factors, the pre-game point spread, and the size of the local viewing audience, we find that upset losses by the home team (losses in games that the home team was predicted to win by more than 3 points) lead to an 8 percent increase in police reports of at-home male-on-female intimate partner violence. There is no corresponding effect on female-on-male violence. Consistent with the behavioral prediction that losses matter more than gains, upset victories by the home team have (at most) a small dampening effect on family violence. We also find that unexpected losses in highly salient or frustrating games have a 50% to 100% larger impact on rates of family violence. The evidence that payoff-irrelevant events affect the rate of family violence leads us to conclude that at least some fraction of family violence is better characterized as a breakdown of control than as an intra-family incentive system. More generally, the empirical findings suggest that gain-loss utility with a rational reference point could be a useful approach to modeling other cues and visceral influences.
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