Protecting a Graph with Mobile Guards

Mobile guards on the vertices of a graph are used to defend it against attacks on either its vertices or its edges. Various models for this problem have been proposed. In this survey we describe a number of these models with particular attention to the case when the attack sequence is infinitely long and the guards must induce some particular configuration before each attack, such as a dominating set or a vertex cover. Results from the literature concerning the number of guards needed to successfully defend a graph in each of these problems are surveyed.Comment: 29 pages, two figures, surve

Empirical Evaluation of Abstract Argumentation: Supporting the Need for Bipolar and Probabilistic Approaches

In dialogical argumentation it is often assumed that the involved parties always correctly identify the intended statements posited by each other, realize all of the associated relations, conform to the three acceptability states (accepted, rejected, undecided), adjust their views when new and correct information comes in, and that a framework handling only attack relations is sufficient to represent their opinions. Although it is natural to make these assumptions as a starting point for further research, removing them or even acknowledging that such removal should happen is more challenging for some of these concepts than for others. Probabilistic argumentation is one of the approaches that can be harnessed for more accurate user modelling. The epistemic approach allows us to represent how much a given argument is believed by a given person, offering us the possibility to express more than just three agreement states. It is equipped with a wide range of postulates, including those that do not make any restrictions concerning how initial arguments should be viewed, thus potentially being more adequate for handling beliefs of the people that have not fully disclosed their opinions in comparison to Dung's semantics. The constellation approach can be used to represent the views of different people concerning the structure of the framework we are dealing with, including cases in which not all relations are acknowledged or when they are seen differently than intended. Finally, bipolar argumentation frameworks can be used to express both positive and negative relations between arguments. In this paper we describe the results of an experiment in which participants judged dialogues in terms of agreement and structure. We compare our findings with the aforementioned assumptions as well as with the constellation and epistemic approaches to probabilistic argumentation and bipolar argumentation

Lawyering in the Christian Colony: Some Hauerwasian Themes, Reflections, and Questions

One who shared Hauerwas\u27s theological commitments might find it difficult to serve as a lawyer, given that the principles of legal ethics are grounded in the kind of political liberalism that Hauerwas finds repellent. For example, Stephen Pepper\u27s well known liberal defense of the standard conception of legal ethics pretty much pushes all of the buttons that set off Hauerwas. Pepper argues that while the law necessarily imposes restrictions on what we may do, but no one else is empowered to place restrictions on our autonomy. In a complex, highly legalistic society, however, citizens are necessarily required in some cases to seek advice from legally trained professionals to determine whether their proposed course of conduct may violate the law, or to employ mechanisms provided for by the legal system (such as contrasts, wills and trusts, and business entities) to achieve their goals. In providing this assistance, lawyers should not impose their own views about the morality of their clients’ conduct; rather, they should assist their clients in implementing their own plans, providing technical assistance but not moral suasion. As any reader of Hauerwas knows, this is an aspect of the modernist anomie he warns about, in which the autonomy to decide for oneself is exalted into the first principle of ethics, with the result that individuals are cut off from the resources they need (traditions, communities, stories) to construct meaningful lives for themselves. This kind of alienation can be cured only by associating oneself with a community -- for Hauerwas this is the church -- and sharing in the ongoing development of its history. Thus, one may ask whether a Christian lawyer can follow some version of the standard conception, at least on Hauerwas\u27s conception of Christian social ethics. With considerable hesitation, given the size and complexity of the corpus of Hauerwas\u27s scholarship, this paper attempts to offer an engaged Christian legal ethics in which the primary obligation of lawyers, acting in their professional capacity, is to respect the law. The linchpin of the argument is a critique of Hauerwas\u27s anti-liberalism. Hauerwas’s objections to liberalism do not hold against a theory of politics that begins with foundational assumptions other than deracinated individuals, and assumes that politics is something more than merely a technology to satisfy pre-existing wants. A different liberal theory might assume, by contrast, that people have reasons to live together in communities and work out a common approach to living together, while treating one another as equals. To the extent there are good theological grounds for treating one another as equals, this version of liberalism can be understood as a political response to God’s presence in the world. A consistent theme in Hauerwas’s work is the dependence of values upon communities, traditions, and stories. I do not see why part of a community’s tradition and self-understanding cannot be pluralism and the corresponding need for some means of dealing with one another despite empirical uncertainty and disagreement about morality. If a community’s history and traditions can be so characterized, then any duties a citizen, public official, or lawyer may have toward the community’s institutions, including the legal system, may be understood as a way of expressing respect for one’s fellow citizens

Wide Sargasso Sea: A Postcolonial Rewriting of Jane Eyre

In her novel Wide Sargasso Sea, Jean Rhys proffers a postcolonial rewriting of Charlotte Brontë’s Jane Eyre. This paper attempts to clarify how Wide Sargasso Sea gives voice to the oriental “Other”, permanently silenced, and deconstructs the European discourse. From a feminist postcolonial perspective, we will try to examine the figures of Antoinette, the colonised, and Mr. Rochester, the coloniser. Ultimately, we will analyse the madness of Antoinette, the Female Other, due to the discord between colonised and coloniser.En su novela Wide Sargasso Sea, Jean Rhys presenta una re-escritura postcolonial de Jane Eyre, de Charlotte Brontë. Este proyecto pretende esclarecer cómo Wide Sargasso Sea da voz a la “otra” oriental, siempre silenciada, y deconstruye la narrativa europea. Para ello, desde una perspectiva feminista y postcolonial, examinaremos los personajes de Antoinette, la colonizada, y Mr. Rochester, el colonizador. Finalmente, analizaremos la locura de Antoinette, la Otra, como resultado del desencuentro entre colonizada y colonizador

He Scores Through a Screen: Mediating Masculinities Through Hockey Video Games

Hockey video games highlight the ways in which the video game medium shapes and conditions the experience of producing and/or performing the sport “in real life.” Indeed, the accumulation of advanced statistics in and through the constant evaluation, measurement, and surveillance which are inherent to video games—and increasingly seen as foundational for sport—reveals important contradictions not only in the way the embodied sport is played and understood, but also in terms of the proofs of masculinity upon which the sport is built. It then becomes clear that the building of masculinity and the empowerment of the character become one and the same. The ludic function reinforces the cultural imperative and vice versa. Thus, our chapter prizes apart the conflation of masculinity with hockey while showing the ways that video game studies can contribute to existing disciplines

Checks, Not Balances

Critics of the administrative state who would revive the nondelegation doctrine and embrace the unitary theory of executive power often assume that each branch’s powers are capable of precise definition, functionally distinct from the others, and that the formal boundaries between each branch are sacrosanct. This Article situates these critiques in Founding Era and nineteenth century debates about the structure of the Constitution. In the 1780s, the AntiFederalists objected to the Constitution for failing to enumerate a precise taxonomy of each branch’s powers, for failing to specify that each branch’s powers were exclusive, and for failing to make government officials sufficiently accountable to the voting public. The drafters responded that the Anti-Federalist approach would neither support effective government nor prevent the branches from acting tyrannically. Rather than develop a scheme of discrete and precisely divided powers, as the Anti-Federalists proposed, the drafters preferred precise rules of inter-branch coordination to ensure that no one branch dominates the others. This debate continued throughout the nineteenth and early twentieth centuries, with influential legal minds such as Daniel Webster and Joseph Story rejecting the Anti-Federalist theory of separation of powers. We call this a theory of separation of powers based on a principle of antidomination. On this view, the separation of powers is breached only if one branch deprives another of its procedural capacity to check the others. We further argue that this theory (a) provides a plausible account of the Framers’ understanding; (b) has had significant purchase in the development of interbranch relations since the Founding and thus can serve as a kind of rational reconstruction of historical practice; and (c) is consistent with the relevant constitutional text and the overall constitutional structure