430 research outputs found

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    A Strong Composition Theorem for Junta Complexity and the Boosting of Property Testers

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    We prove a strong composition theorem for junta complexity and show how such theorems can be used to generically boost the performance of property testers. The ε\varepsilon-approximate junta complexity of a function ff is the smallest integer rr such that ff is ε\varepsilon-close to a function that depends only on rr variables. A strong composition theorem states that if ff has large ε\varepsilon-approximate junta complexity, then g∘fg \circ f has even larger ε′\varepsilon'-approximate junta complexity, even for ε′≫ε\varepsilon' \gg \varepsilon. We develop a fairly complete understanding of this behavior, proving that the junta complexity of g∘fg \circ f is characterized by that of ff along with the multivariate noise sensitivity of gg. For the important case of symmetric functions gg, we relate their multivariate noise sensitivity to the simpler and well-studied case of univariate noise sensitivity. We then show how strong composition theorems yield boosting algorithms for property testers: with a strong composition theorem for any class of functions, a large-distance tester for that class is immediately upgraded into one for small distances. Combining our contributions yields a booster for junta testers, and with it new implications for junta testing. This is the first boosting-type result in property testing, and we hope that the connection to composition theorems adds compelling motivation to the study of both topics.Comment: 44 pages, 1 figure, FOCS 202

    Malleable zero-knowledge proofs and applications

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    In recent years, the field of privacy-preserving technologies has experienced considerable expansion, with zero-knowledge proofs (ZKPs) playing one of the most prominent roles. Although ZKPs have been a well-established theoretical construct for three decades, recent efficiency improvements and novel privacy applications within decentralized finance have become the main drivers behind the surge of interest and investment in this area. This momentum has subsequently sparked unprecedented technical advances. Non-interactive ZKPs (NIZKs) are now regularly implemented across a variety of domains, encompassing, but not limited to, privacy-enabling cryptocurrencies, credential systems, voting, mixing, secure multi-party computation, and other cryptographic protocols. This thesis, although covering several areas of ZKP technologies and their application, focuses on one important aspect of NIZKs, namely their malleability. Malleability is a quality of a proof system that describes the potential for altering an already generated proof. Different properties may be desired in different application contexts. On the one end of the spectrum, non-malleability ensures proof immutability, an important requirement in scenarios such as prevention of replay attacks in anonymous cryptocurrencies. At the other end, some NIZKs enable proof updatability, recursively and directly, a feature that is integral for a variety of contexts, such as private smart contracts, compact blockchains, ZK rollups, ZK virtual machines, and MPC protocols generally. This work starts with a detailed analysis of the malleability and overarching security of a popular NIZK, known as Groth16. Here we adopt a more definitional approach, studying certain properties of the proof system, and its setup ceremony, that are crucial for its precise modelling within bigger systems. Subsequently, the work explores the malleability of transactions within a private cryptocurrency variant, where we show that relaxing non-malleability assumptions enables a functionality, specifically an atomic asset swap, that is useful for cryptocurrency applications. The work culminates with a study of a less general, algebraic NIZK, and particularly its updatability properties, whose applicability we present within the context of ensuring privacy for regulatory compliance purposes

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    Tennyson's Figures of Repetition

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    This thesis argues that Tennyson’s uses of repetition can be seen not merely as a manifestation of his sometimes alleged ‘stupidity’ but as an embodiment of his continual self-questioning and self-criticism. To do this, I focus on five figures of repetition: memory/Memory (Chapter 1), mirror-images (Chapter 2), simile (Chapter 3), antithesis (Chapter 4), fama/Fama (Chapter 5). My first chapter begins by considering the way in which Tennyson’s act of recollection is accompanied by the idealisation of the past and the denigration of the present. It then sees the reverse of a recollection within Tennyson’s representation of Memory, and in his use of memory. My second chapter examines Tennyson’s descriptions of mirror-image, showing how this shadowy existence is not simply presented as an inferior reproduction of the original, but comes to assume its own substantiality. My third chapter shows how In Memoriam’s conflicting processes of unity and division are encapsulated in the relationship between the words in the rhetorical figure of the simile. It shows how the poem’s use of simile reveals the tension between the unitive and disjunctive tendencies of language itself, presenting the poem as a critique of the Romantic, metaphorical view of language. My fourth chapter shows how in Maud the speaker’s doubts about his control over the action are communicated through the antithetical repetition of the same verb in the two grammatical voices. My fifth chapter examines how in Idylls of the King Arthur’s authority, which is connected to Tennyson’s authority, is dependent upon repetitive and diffusive speech. It argues that such a derivation of authority from the diffusion of speech is registered in the semantic duplexities of the Latin word fama/Fama. My conclusion considers Tennyson’s posthumous fame as a kind of repetition in itself, examining the way T. S. Eliot remodels Tennyson’s homes in ‘East Coker’

    Translating the poetry of Cécile Sauvage: love and creativity in practice

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    This project is composed of a critical discussion about translating the French writer Cécile Sauvage (1883-1927) and a creative translation of selected Sauvage poems into English. Informed by creative critical theories, this project examines the personal stakes residing within this academic framework. Chapter 1 takes up the concept of fannishness as a method of participating in a cultural product. I define fannishness as love for a text, imagine the translator as a fan, and analyze metaphors of spatial distance used to describe creation and criticism. In Chapter 2, I examine the reception of Sauvage’s poetry, arguing that the historical treatment of Sauvage as a ‘woman poet’ has implications for translation. In Chapter 3, I examine how feminist theorists have dealt with Sauvage; drawing upon feminist and queer theories of translation, I connect translation to violence and love. In Chapter 4, I describe my approach to translating Sauvage on the formal level, drawing upon Jean Boase-Beier and Clive Scott to argue that a successful translation is one that embraces the translator’s positioning and extends the source text’s existence in a new way. In Chapter 5, I suggest that anthologizing or editing Sauvage means rewriting her. As I recount my trip to Sauvage’s archives, I bridge translation and editing, arguing that a translation is an extension of a text’s genesis. Chapter 6 discusses the reasoning behind the form, content and presentation of my translated collection, A Sauvage Reader. The Reader follows, interspersed with poetic commentary and quoted intertexts. The six themes that organize the Reader connect to creative critical vocabulary and to metaphors of translation. I conclude that my translation has given Sauvage’s work a new narrative, chronicled a translator’s experience, and brought to Translation Studies a novel articulation of how translators, like scholars, acknowledge relations of partiality, or what I call love
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