Relating L-Resilience and Wait-Freedom via Hitting Sets

The condition of t-resilience stipulates that an n-process program is only obliged to make progress when at least n-t processes are correct. Put another way, the live sets, the collection of process sets such that progress is required if all the processes in one of these sets are correct, are all sets with at least n-t processes. We show that the ability of arbitrary collection of live sets L to solve distributed tasks is tightly related to the minimum hitting set of L, a minimum cardinality subset of processes that has a non-empty intersection with every live set. Thus, finding the computing power of L is NP-complete. For the special case of colorless tasks that allow participating processes to adopt input or output values of each other, we use a simple simulation to show that a task can be solved L-resiliently if and only if it can be solved (h-1)-resiliently, where h is the size of the minimum hitting set of L. For general tasks, we characterize L-resilient solvability of tasks with respect to a limited notion of weak solvability: in every execution where all processes in some set in L are correct, outputs must be produced for every process in some (possibly different) participating set in L. Given a task T, we construct another task T_L such that T is solvable weakly L-resiliently if and only if T_L is solvable weakly wait-free

Randomized protocols for asynchronous consensus

The famous Fischer, Lynch, and Paterson impossibility proof shows that it is impossible to solve the consensus problem in a natural model of an asynchronous distributed system if even a single process can fail. Since its publication, two decades of work on fault-tolerant asynchronous consensus algorithms have evaded this impossibility result by using extended models that provide (a) randomization, (b) additional timing assumptions, (c) failure detectors, or (d) stronger synchronization mechanisms than are available in the basic model. Concentrating on the first of these approaches, we illustrate the history and structure of randomized asynchronous consensus protocols by giving detailed descriptions of several such protocols.Comment: 29 pages; survey paper written for PODC 20th anniversary issue of Distributed Computin

Elitism vs. Checks and Balances in Communicating Scientific Information to the Public

The father of the Science Court describes his objective in proposing the institution as it has come to be known, his efforts to get a major public test of the concept, and insights gained since the initial proposal was made in 1967

Bringing Wreck

This paper critically examines non-adversarial feminist argumentation model specifically within the scope of politeness norms and cultural communicative practices. Asserting women typically have a particular mode of arguing which is often seen as ‘weak’ or docile within male dominated fields, the model argues that the feminine mode of arguing is actually more affiliative and community orientated, which should become the standard within argumentation as opposed to the Adversary Method. I argue that the nonadversarial feminist argumentation model primarily focuses on one demographic of women’s communicative styles – white women. Taking an intersectional approach, I examine practices within African American women’s speech communities to illustrate the ways in which the virtues and vices purported by the NAFAM fails to capture other ways of productive argumentation

Restoring Bankruptcy’s Fresh Start

The discharge injunction, which allows former debtors to be free from any efforts to collect former debt, is a primary feature of bankruptcy law in the United States. When creditors have systemically violated debtors’ discharge injunctions, some debtors have attempted to challenge those creditors through a class action lawsuit in bankruptcy court. However, the pervasiveness of class-waiving arbitration clauses likely prevents those debtors from disputing discharge injunction violations outside of binding, individual arbitration. This Note first discusses areas of disagreement regarding how former debtors may enforce their discharge injunctions. Then, it examines the types of disputes that allow debtors to collectivize in bankruptcy court. Without seeking to resolve either disagreement, this Note assumes debtors may collectivize in this context and employs an “inherent conflict” test that looks to whether disputes over discharge injunction violations are arbitrable. Because the “inherent conflict” test likely leads to the conclusion that courts must enforce class-waiving arbitration clauses, this Note argues that Congress should amend the Bankruptcy Code not only to provide debtors an express right of action under § 524 and the ability to collectivize, but also to prohibit the arbitration of these claims. Doing so will give full effect to the discharge injunction and fulfill the promise to debtors that they can truly begin anew after bankruptcy

Quantum Certificate Complexity

Given a Boolean function f, we study two natural generalizations of the certificate complexity C(f): the randomized certificate complexity RC(f) and the quantum certificate complexity QC(f). Using Ambainis' adversary method, we exactly characterize QC(f) as the square root of RC(f). We then use this result to prove the new relation R0(f) = O(Q2(f)^2 Q0(f) log n) for total f, where R0, Q2, and Q0 are zero-error randomized, bounded-error quantum, and zero-error quantum query complexities respectively. Finally we give asymptotic gaps between the measures, including a total f for which C(f) is superquadratic in QC(f), and a symmetric partial f for which QC(f) = O(1) yet Q2(f) = Omega(n/log n).Comment: 9 page