On sets of numbers rationally represented in a rational base number system

In this work, it is proved that a set of numbers closed under addition and whose representations in a rational base numeration system is a rational language is not a finitely generated additive monoid. A key to the proof is the definition of a strong combinatorial property on languages : the bounded left iteration property. It is both an unnatural property in usual formal language theory (as it contradicts any kind of pumping lemma) and an ideal fit to the languages defined through rational base number systems

Cryptographically Secure Information Flow Control on Key-Value Stores

We present Clio, an information flow control (IFC) system that transparently incorporates cryptography to enforce confidentiality and integrity policies on untrusted storage. Clio insulates developers from explicitly manipulating keys and cryptographic primitives by leveraging the policy language of the IFC system to automatically use the appropriate keys and correct cryptographic operations. We prove that Clio is secure with a novel proof technique that is based on a proof style from cryptography together with standard programming languages results. We present a prototype Clio implementation and a case study that demonstrates Clio's practicality.Comment: Full version of conference paper appearing in CCS 201

Solving Parity Games in Scala

Parity games are two-player games, played on directed graphs, whose nodes are labeled with priorities. Along a play, the maximal priority occurring infinitely often determines the winner. In the last two decades, a variety of algorithms and successive optimizations have been proposed. The majority of them have been implemented in PGSolver, written in OCaml, which has been elected by the community as the de facto platform to solve efficiently parity games as well as evaluate their performance in several specific cases. PGSolver includes the Zielonka Recursive Algorithm that has been shown to perform better than the others in randomly generated games. However, even for arenas with a few thousand of nodes (especially over dense graphs), it requires minutes to solve the corresponding game. In this paper, we deeply revisit the implementation of the recursive algorithm introducing several improvements and making use of Scala Programming Language. These choices have been proved to be very successful, gaining up to two orders of magnitude in running time

What Are They and How Do I Use Them?: Strategies and Tools to Increase and Improve Filing of the Federal Hope and Lifetime Learning Education Tax Credits by Low-Income Filers

Provides an overview of education tax credits, and suggests strategies to address operational and policy issues that prevent low-income families from filing for them. Includes samples of awareness-raising material and a guide for volunteer tax preparers

Semantic Holism Revisited

I defend semantic holism, the view that the meaning of an expression is determined by its relations to every other expression in the language of individual competent users. I argue that, once properly understood, most disadvantages attributed to holism can be dissolved and suggest that the core division between the holist and the non-holist is on the question whether invariant meanings shared across all possible occasions where the corresponded expressions are uttered are necessary for the explanation of meaning sharing. I give reason why the answer is negative and demonstrate how to explain our linguistic interaction without such invariant meanings