Person Games Research Articles

SLGAD Resolution for Inference on Logic Programs with Annotated Disjunctions

Logic Programs with Annotated Disjunctions (LPADs) allow to express probabilistic information in logic programming. The semantics of an LPAD is given in terms of the well-founded models of the normal logic programs obtained by selecting one disjunct from each ground LPAD clause. Inference on LPADs can be performed using either the system Ailog2, that was developed for the Independent Choice Logic, or SLDNFAD, an algorithm based on SLDNF. However, both of these algorithms run the risk of going into infinite loops and of performing redundant computations. In order to avoid these problems, we present SLGAD resolution that computes the (conditional) probability of a ground query from a range-restricted LPAD and is based on SLG resolution for normal logic programs. As SLG, it uses tabling to avoid some infinite loops and to avoid redundant computations. The performances of SLGAD are evaluated on classical benchmarks for normal logic programs under the well-founded semantics, namely a 2-person game and the ancestor relation, and on games of dice. SLGAD is compared with Ailog2 and SLDNFAD on the problems in which they do not go into infinite loops, namely those that are described by a modularly acyclic program. The results show that SLGAD is sometimes slower than Ailog2 and SLDNFAD but, if the program requires the repeated computations of the same goals, as for the dice games, then SLGAD is faster than both.

Tribute to John Paul Stevens

Tribute to John Paul Stevens DAVID H. SOUTER Justice Stevens is supposed to be older than I am, but the evidence is mixed. I remember one morning back in June of 2009, for example, when he and I happened to get to work atjust the same time. I was in a suit, but John was still in tennis shorts, after one of his four weekly singles matches at 7:00 a.m. (He usually arrived in civvies.) I asked him, how’d the game go. There was a little victory leap. “I really beat him.” John’s a player. Which is enough to make you wonder why the old urge to win another game didn’t keep him on the Bench forjust two years and a few days more, all it would have taken to pass Jus­ tice Douglas’s record tenure. There was no rea­ son he had to step down from the one Court while he was still running aroundthe other one; he had deputized me to tell him if he stayed too long, thereby giving me the only sinecure I ever held. And it’s not as though he only skir­ mished on a tennis court: consider the bridge playing and dissents like Citizens United.1 But the Supreme Court isn’t a personal game, and there’s more to John Stevens than the player. He doesn’t live his life reacting to the way others live theirs, any more than he ever felt a need to know how someone else on the Court viewed a case before he decided what to do on it himself. You could see it in the way he worked over the years. Justices range all over the spectrum of inclination (or not) to talk about the argued cases in the couple of days between coming off the Bench and sit­ ting down at conference. John’s door was al­ ways open to anyone who wanted to bat some­ thing around, but he was hardly ever (maybe never) the one to ask about a colleague’s take on an issue before all nine of us were sitting down together, ready for the first pass at it. He thought the Court would do its best thinking if we brought our own thinking fresh to the table; the singular insight was less likely to get lost in hasty consensus, and any homogenizing could be donejust as well after conference. He didn’t reach out for the comfort ofpre-agreement. And a good thing that was, for often enough he was the one who saw something the rest ofus didn’t, or saw it in some way we didn’t, especially in those cases that challenge the best of judges to stay awake. The Court has its share of them, usually raising statu­ tory construction issues: is the clause limiting something orjust giving a random illustration? Matters like that. It’s not that you let yourself 196 JOURNAL OF SUPREME COURT HISTORY John Paul Stevens was assigned to a code-breaking team from 1942 to 1945 and earned a Bronze Star for his service in 1946. While stationed in Pearl Har­ bor, Hawaii, he served as a watch officer analyzing intercepted Japanese communications. give them short shrift when they come along; they just don’t stimulate. When it was time to take up one like that at conference, I (at least) might be sitting there with a weak pulse, and then it would be John’s turn, and we’d hear something like this: “You know, when you get into it, this is really a fascinating little case.” And he’d mean it, and he’d say why. He might not get eight other votes for “fascinating,” but he’d give the case a shot of pep it hadn’t had before. No appellatejudge I’ve ever known has done more honor to the rule an old New Hamp­ shire trial judge told me years ago: “There are no unimportant cases.” That’s not so hard to remember when the parties are right there in front of you in a trial courtroom, but John didn’t seem to have any trouble realizing it two courts...

The graying of academia: Will it reduce scientific productivity?

The belief that science is a young person's game and that only young scientists can be productive and publish high-quality research is still widely shared by university administrators and members of the scientific community. Since the average age of university faculties is increasing not only in the United States but also in Europe, the question arises as to whether this belief is correct. If it were valid, the abolition of compulsory retirement in the United States and some parts of Canada would lower the productivity of these university systems. To address this question, this article reviews research on the association of age and scientific productivity conducted during the last four decades in North America and Europe. Whereas early research typically showed a decline in productivity after the ages of 40 to 45 years, this decline has been absent in more recent studies. Explanations for this change are discussed.

Min, a Combinatorial Game Having a Connection with Prime Numbers

AbstractWe introduce a two person game played with a pair of nonnegative integers; a move consists of subtracting from the larger integer, a positive integer no greater than the smaller integer. The player who reduces one of the integers to zero wins. The game is curious in several respects: in particular, its Sprague–Grundy values have an interesting connection with prime numbers.

Games for Truth

AbstractWe represent truth sets for a variety of the well known semantic theories of truth as those sets consisting of all sentences for which a player has a winning strategy in an infinite two person game. The classifications of the games considered here are simple, those over the natural model of arithmetic being all within the arithmetical class of .

Children’s Electronic Gaming Content Preferences and Psychosocial Factors

AbstractThe gaming industry has dramatically increased the range of choices for different game genres and content. Despite this, research on psychosocial factors in children and electronic gaming has primarily focused on time spent on games rather than on content preferences. The present study goes beyond the traditional focus on electronic game frequency by investigating whether children’s personal gaming content preferences are associated with psychosocial factors (self-concept, social competence and parental monitoring). This is accomplished by surveying 825 schoolchildren between ten and twelve years of age (5th, 6thand 7thgrade) in Norway. A preference for violent games was moderately associated with low social acceptance among peers. Preference for pedagogical games was associated with high scholastic and athletic competence as well as perceived levels of parental monitoring. A preference for fantasy gaming was positively related to scholastic competence. Finally, preference for competitive games was strongly associated with experienced athletic competence.

Simple complexity from imitation games

We give simple proofs of refinements of the complexity results of Gilboa and Zemel (1989), and we derive additional results of this sort. Our constructions employ imitation games, which are two person games in which both players have the same sets of pure strategies and the second player wishes to play the same pure strategy as the first player.

Social Responsibility Tools in Online Gambling: A Survey of Attitudes and Behavior among Internet Gamblers

To date, little empirical research has focused on social responsibility in gambling. This study examined players' attitudes and behavior toward using the social responsibility tool PlayScan designed by the Swedish gaming company Svenska Spel. Via PlayScan, players have the option to utilize various social responsibility control tools (e.g., personal gaming budgets, self-diagnostic tests of gambling habits, self-exclusion options). A total of 2,348 participants took part in an online questionnaire study. Participants were clientele of the Svenska Spel online gambling Web site. Results showed that just over a quarter of players (26%) had used PlayScan. The vast majority of those who had activated PlayScan (almost 9 in 10 users) said that PlayScan was easy to use. Over half of PlayScan users (52%) said it was useful; 19% said it was not. Many features were seen as useful by online gamblers, including limit setting (70%), viewing their gambling profile (49%), self-exclusion facilities (42%), self-diagnostic problem gambling tests (46%), information and support for gambling issues (40%), and gambling profile predictions (36%). In terms of actual (as opposed to theoretical) use, over half of PlayScan users (56%) had set spending limits, 40% had taken a self-diagnostic problem gambling test, and 17% had used a self-exclusion feature.

I Want You! An Experiment Studying the Selection Effect when Assigning Distributive Power

Trabajo publicado como articulo en Labour Economics 13(1): 1-17 (2006) con el titulo I want YOU! An experiment studying motivational effects when assigning distributive power.-- http://dx.doi.org/10.1016/j.labeco.2004.08.003

Directed defective asymmetric graph coloring games

We consider the following 2-person game which is played with an (initially uncolored) digraph D , a finite color set C , and nonnegative integers a , b , and d . Alternately, player I colors a vertices and player II colors b vertices with colors from C . Whenever a player colors a vertex v , all in-arcs ( w , v ) that do not come from a vertex w previously colored with the same color as v are deleted. For each color i the defect digraph D i is the digraph induced by the vertices of color i at a certain state of the game. The main rule the players have to respect is that at every time for any color i the digraph D i has maximum total degree of at most d . The game ends if no vertex can be colored any more according to this rule. Player I wins if D is completely colored at the end of the game, otherwise player II wins. The smallest cardinality of a color set C with which player I has a winning strategy for the game is called d - r e l a x e d ( a , b ) - g a m e c h r o m a t i c n u m b e r of D . This parameter generalizes several variants of Bodlaender’s game chromatic number. We determine the tight (resp., nearly tight) upper bound ⌊ b d + 1 ⌋ + 2 (resp., ⌊ b d + 1 ⌋ + 3 ) for the d -relaxed ( a , b ) -game chromatic number of orientations of forests (resp., undirected forests) for any d and a ≥ b ≥ 1 . Furthermore we prove that these numbers cannot be bounded in case a < b .

Assessing Combat Medic Knowledge and Transfer Effects Resulting from Alternative Training Treatments

While advocacy of gaming tools to support training has been a trend observed in recent years, little definitive empirical research regarding the effectiveness of games in training has been established. This research focused on an instructional game developed by the US Army to support Tactical Combat Casualty Care (TC3). The TC3 Game-based Simulation is a first person game where the trainee plays the role of a medic assigned to a light infantry squad operating in an urban environment. This research focuses on training treatments and the potential use of computer games as experiential tools for learning by Soldiers. In an effort to draw empirical results, it was the objective of this research to evaluate the training effectiveness using the TC3 Game-based Simulation following Kirkpatrick’s four-level model and comparing it to multimedia and interactive modes of instruction. Reaction to training was explored, as were the acquisition of knowledge and the transfer of skills. The acquisition of knowledge occurred for participants in all treatments and significant statistical differences were found in gain scores between participants in the multimedia group and participants with interactive modes of instruction. In addition, significant statistical differences were found in transfer task scores between participants in the multimedia group and participants with interactive modes of instruction.

Fixed point theorems and existence of equilibrium points of noncompact abstract economies for [formula omitted]-majorized mappings in [formula omitted]-spaces

In this paper, we first establish two fixed point theorems in noncompact F C -spaces. Next two existence theorems of maximal elements for L F ∗ -correspondence and L F ∗ -majorized correspondence are obtained. Finally, by applying the existence theorems of maximal elements, some new equilibrium existence theorems for one person game, qualitative games and noncompact abstract economies with L F ∗ -majorized correspondences are obtained in F C -spaces. These results generalize some known results in recent literature.

Conformity, reciprocity and the sense of justice. How social contract-based preferences and beliefs explain norm compliance: the experimental evidence

Compliance with a social norm is a matter of self-enforceability and endogenous motivation to conform which is relevant not just to social norms but also to a wide array of institutions. Here we consider endogenous mechanisms that become effective once the game description has been enriched with pre-play communication allowing impartial agreements on a norm (even if they remain not binding in any sense). Behavioral models understand conformity as the maximization of some “enlarged” utility function properly defined to make room for the individual’s “desire” to comply with a norm reciprocally adhered to by other participants—whose conformity in turn depends on the expectation that the norm will be in fact reciprocally adhered to. In particular this paper presents an experimental study on the “conformity-with-the-ideal preference theory” (Grimalda and Sacconi in Const Polit Econ 16(3):249–276, 2005), based on a simple experimental three person game called the “exclusion game”. If the players participate in a “constitutional stage” (under a veil of ignorance) in which they decide the rule of division unanimously, the experimental data show a dramatic change in the participants’ behavior pattern. Most of them conform to the fair rule of division to which they have agreed in a pre-play communication stage, whereas in the absence of this agreement they behave more egoistically. The paper also argues that this behavior is largely consistent with what Rawls (A theory of justice, Oxford University Press, Oxford, 1971) called the “sense of justice”, a theory of norm compliance unfortunately overlooked by economists and which should be reconsidered after the behaviorist turn in economics.

"Once more a kingly quest": Fan games and the classic adventure genre

The classic adventure games—part of the earliest traditions of interactive narrative—have not disappeared, although they no longer occupy space on the shelves at the local computer store. Even as changing hardware and operating systems render these games of the 1980s and 1990s literally unplayable without emulating the computer systems of the past, fans are keeping these stories alive. Authorship of these games has changed hands: it is now under the control of the fans, the former and current players. Through the online sharing of fan-created game design tool sets and of the fan-created games themselves, these new coauthors create a haven to revisit these decades-old games using fresh eyes and fresh systems. The products of these folk art–reminiscent efforts also offer a venue to reconsider video game fandom in light of genres. They also allow us to understand these "personal games," productions of one or more people that are not intended for commercial sale, as carrying the heritage of the classic era forward into the next generation of gaming.

Homotopy methods to compute equilibria in game theory

This paper presents a survey of the use of homotopy methods in game theory. Homotopies allow for a robust computation of game-theoretic equilibria and their refinements. Homotopies are also suitable to compute equilibria that are selected by various selection theories. We present the relevant techniques underlying homot- opy algorithms. We give detailed expositions of the Lemke-Howson algorithm and the van den Elzen-Talman algorithm to compute Nash equilibria in 2-person games, and the Herings-van den Elzen, Herings-Peeters, and McKelvey-Palfrey algorithms to compute Nash equilibria in general n-person games. We explain how the main ideas can be extended to compute equilibria in extensive form and dynamic games, and how homotopies can be used to compute all Nash equilibria.

Lobbying in the New Millennium: Evidence of Continuity and Change in Three States

AbstractWe report the results of a survey of over 300 lobbyists in three states—Colorado, Ohio, and West Virginia. In the first half of this article, we provide a comprehensive portrait of state lobbyists' attempts to affect state government decisions. In the second half, we address the following research question: What factors affect the lobbying behavior of state lobbyists? Our results suggest a number of conclusions about lobbying in the new millennium, including the following: (1) state lobbyists target the governor's office more than most previous studies suggest; (2) state lobbyists aim their grassroots lobbying efforts at the governor and executive agency bureaucrats as well as legislators; (3) state lobbying remains an intensely personal game, as techniques involving face-to-face contact with government officials remain the most effective; and (4) several variables affect a lobbyist's decisions regarding which techniques to use and where to aim his or her efforts, including the receptivity of potential targets and the type of group for which the lobbyist works.

"Once more a kingly quest": Fan games and the classic adventure genre

The classic adventure games—part of the earliest traditions of interactive narrative—have not disappeared, although they no longer occupy space on the shelves at the local computer store. Even as changing hardware and operating systems render these games of the 1980s and 1990s literally unplayable without emulating the computer systems of the past, fans are keeping these stories alive. Authorship of these games has changed hands: it is now under the control of the fans, the former and current players. Through the online sharing of fan-created game design tool sets and of the fan-created games themselves, these new coauthors create a haven to revisit these decades-old games using fresh eyes and fresh systems. The products of these folk art–reminiscent efforts also offer a venue to reconsider video game fandom in light of genres. They also allow us to understand these personal games, productions of one or more people that are not intended for commercial sale, as carrying the heritage of the classic era forward into the next generation of gaming.

Uniqueness of values of Aronsson operators and running costs in “tug-of-war” games

Let AH be the Aronsson operator associated with a Hamiltonian H(x,z,p). Aronsson operators arise from L∞ variational problems, two person game theory, control problems, etc. In this paper, we prove, under suitable conditions, that if u∊Wloc1,∞(Ω) is simultaneously a viscosity solution of both of the equations(0.1)AH(u)=f(x)andAH(u)=g(x)in Ω, where f,g∊C(Ω), then f=g. The assumption u∊Wloc1,∞(Ω) can be relaxed to u∊C(Ω) in many interesting situations. Also, we prove that if f,g,u∊C(Ω) and u is simultaneously a viscosity solution of the equations(0.2)Δ∞u|Du|2=−f(x)andΔ∞u|Du|2=−g(x)in Ω, then f=g. This answers a question posed in Peres, Schramm, Scheffield and Wilson [Y. Peres, O. Schramm, S. Sheffield, D.B. Wilson, Tug-of-war and the infinity Laplacian, J. Amer. Math. Soc. Math. 22 (2009) 167–210] concerning whether or not the value function uniquely determines the running cost in the “tug-of-war” game.

Learning in games with unstable equilibria

We propose a new concept for the analysis of games, the TASP, which gives a precise prediction about non-equilibrium play in games whose Nash equilibria are mixed and are unstable under fictitious play-like learning. We show that, when players learn using weighted stochastic fictitious play and so place greater weight on recent experience, the time average of play often converges in these “unstable” games, even while mixed strategies and beliefs continue to cycle. This time average, the TASP, is related to the cycle identified by Shapley [L.S. Shapley, Some topics in two person games, in: M. Dresher, et al. (Eds.), Advances in Game Theory, Princeton University Press, Princeton, 1964]. The TASP can be close to or quite distinct from Nash equilibrium.

Context as Support for Learning Computer Organization

The ubiquity of personal computational devices in the lives of today's students presents a meaningful context for courses in computer organization beyond the general-purpose or imaginary processors routinely used. This article presents results of a comparative study examining student performance in a conventional organization course and in one that has been contextualized using a personal gaming platform as the pedagogical architecture. We find minimal differences in student learning but significant motivation and engagement gains for those in the contextualized course.