133 research outputs found

    LIPIcs, Volume 251, ITCS 2023, Complete Volume

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    LIPIcs, Volume 251, ITCS 2023, Complete Volum

    Search versus Search for Collapsing Electoral Control Types

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    Electoral control types are ways of trying to change the outcome of elections by altering aspects of their composition and structure [BTT92]. We say two compatible (i.e., having the same input types) control types that are about the same election system E form a collapsing pair if for every possible input (which typically consists of a candidate set, a vote set, a focus candidate, and sometimes other parameters related to the nature of the attempted alteration), either both or neither of the attempted attacks can be successfully carried out [HHM20]. For each of the seven general (i.e., holding for all election systems) electoral control type collapsing pairs found by Hemaspaandra, Hemaspaandra, and Menton [HHM20] and for each of the additional electoral control type collapsing pairs of Carleton et al. [CCH+ 22] for veto and approval (and many other election systems in light of that paper's Theorems 3.6 and 3.9), both members of the collapsing pair have the same complexity since as sets they are the same set. However, having the same complexity (as sets) is not enough to guarantee that as search problems they have the same complexity. In this paper, we explore the relationships between the search versions of collapsing pairs. For each of the collapsing pairs of Hemaspaandra, Hemaspaandra, and Menton [HHM20] and Carleton et al. [CCH+ 22], we prove that the pair's members' search-version complexities are polynomially related (given access, for cases when the winner problem itself is not in polynomial time, to an oracle for the winner problem). Beyond that, we give efficient reductions that from a solution to one compute a solution to the other. For the concrete systems plurality, veto, and approval, we completely determine which of their (due to our results) polynomially-related collapsing search-problem pairs are polynomial-time computable and which are NP-hard.Comment: The metadata's abstract is abridged due to arXiv.org's abstract-length limit. The paper itself has the unabridged (i.e., full) abstrac

    Recent Advances in Research on Island Phenomena

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    In natural languages, filler-gap dependencies can straddle across an unbounded distance. Since the 1960s, the term “island” has been used to describe syntactic structures from which extraction is impossible or impeded. While examples from English are ubiquitous, attested counterexamples in the Mainland Scandinavian languages have continuously been dismissed as illusory and alternative accounts for the underlying structure of such cases have been proposed. However, since such extractions are pervasive in spoken Mainland Scandinavian, these languages may not have been given the attention that they deserve in the syntax literature. In addition, recent research suggests that extraction from certain types of island structures in English might not be as unacceptable as previously assumed either. These findings break new empirical ground, question perceived knowledge, and may indeed have substantial ramifications for syntactic theory. This volume provides an overview of state-of-the-art research on island phenomena primarily in English and the Scandinavian languages, focusing on how languages compare to English, with the aim to shed new light on the nature of island constraints from different theoretical perspectives

    Towards a logical foundation of randomized computation

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    This dissertation investigates the relations between logic and TCS in the probabilistic setting. It is motivated by two main considerations. On the one hand, since their appearance in the 1960s-1970s, probabilistic models have become increasingly pervasive in several fast-growing areas of CS. On the other, the study and development of (deterministic) computational models has considerably benefitted from the mutual interchanges between logic and CS. Nevertheless, probabilistic computation was only marginally touched by such fruitful interactions. The goal of this thesis is precisely to (start) bring(ing) this gap, by developing logical systems corresponding to specific aspects of randomized computation and, therefore, by generalizing standard achievements to the probabilistic realm. To do so, our key ingredient is the introduction of new, measure-sensitive quantifiers associated with quantitative interpretations. The dissertation is tripartite. In the first part, we focus on the relation between logic and counting complexity classes. We show that, due to our classical counting propositional logic, it is possible to generalize to counting classes, the standard results by Cook and Meyer and Stockmeyer linking propositional logic and the polynomial hierarchy. Indeed, we show that the validity problem for counting-quantified formulae captures the corresponding level in Wagner's hierarchy. In the second part, we consider programming language theory. Type systems for randomized \lambda-calculi, also guaranteeing various forms of termination properties, were introduced in the last decades, but these are not "logically oriented" and no Curry-Howard correspondence is known for them. Following intuitions coming from counting logics, we define the first probabilistic version of the correspondence. Finally, we consider the relationship between arithmetic and computation. We present a quantitative extension of the language of arithmetic able to formalize basic results from probability theory. This language is also our starting point to define randomized bounded theories and, so, to generalize canonical results by Buss

    Bisimulations for Kripke models of Fuzzy Multimodal Logics

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    The main objective of the dissertation is to provide a detailed study of several different types of simulations and bisimulations for Kripke models of fuzzy multimodal logics. Two types of simulations (forward and backward) and five types of bisimulations (forward, backward, forward-backward, backward-forward and regular) are presented hereby. For each type of simulation and bisimulation, an algorithm is created to test the existence of the simulation or bisimulation and, if it exists, the algorithm computes the greatest one. The dissertation presents the application of bisimulations in the state reduction of fuzzy Kripke models, while preserving their semantic properties. Next, weak simulations and bisimulations were considered and the Hennessy-Milner property was examined. Finally, an algorithm was created to compute weak simulations and bisimulations for fuzzy Kripke models over locally finite algebras

    The Holocaust in Three Generations

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    What form does the dialogue about the family past during the Nazi period take in families of those persecuted by the Nazi regime and in families of Nazi perpetrators and bystanders? What impact does the past of the first generation, and their own way of dealing with it have on the lives of their children and grandchildren?What are the differences between the dialogue about the family past and the Holocaust in families of Nazi perpetrators and in families of Holocaust survivors?This book examines these questions on the basis of selected case studies

    \u27Play the Book Again\u27: Towards a Systems Approach to Game Adaptation

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    Situated at the interstices of game studies, adaptation scholarship, and literary theory, this dissertation puts forth a theoretical framework for effectively analyzing literary game adaptations (that is, playable digital or analog systems that are based upon a work or works of literature) as expressive intertextual systems which facilitate aesthetic experiences. By integrating contemporary game studies with filmic adaptation studies and literary theory, I argue that game adaptations allow us to see how games, adaptations, and indeed all texts can be productively conceived of as Barthesian networks of meaning: collections of interacting formal, narrative, intertextual, and contextual elements from which a user\u27s experience arises. Doing so destabilizes the primacy of concepts that are so often used to justify hierarchical relationships between high art and popular culture, opening up new interpretations of texts which do not lend themselves to analysis via traditional literary or cinematic methodologies. Thinking of adaptations in terms of the systemized relationships between texts, intertexts, and the user rather than as merely derivative copies of a single original also redefines the classically hierarchical relationship between adaptations and their sources that has plagued adaptation studies discourse from its inception. Through my readings of a variety of digital and analog games based on William Shakespeare\u27s Hamlet (Ryan North\u27s gamebook To Be or Not to Be), J.R.R. Tolkien\u27s The Hobbit (Beam Software\u27s Hobbit text-adventure), Jane Austen\u27s Pride and Prejudice (Storybrewers\u27 tabletop roleplaying game Good Society), and Henry David Thoreau\u27s Walden (Tracy Fullerton\u27s contemplative digital walking simulator Walden, a game), I illustrate how thinking of texts as systems affords interpretatively productive play, encouraging users to reinterpret, revise, and remix culture to their own ends

    Automated Reasoning

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    This volume, LNAI 13385, constitutes the refereed proceedings of the 11th International Joint Conference on Automated Reasoning, IJCAR 2022, held in Haifa, Israel, in August 2022. The 32 full research papers and 9 short papers presented together with two invited talks were carefully reviewed and selected from 85 submissions. The papers focus on the following topics: Satisfiability, SMT Solving,Arithmetic; Calculi and Orderings; Knowledge Representation and Jutsification; Choices, Invariance, Substitutions and Formalization; Modal Logics; Proofs System and Proofs Search; Evolution, Termination and Decision Prolems. This is an open access book

    The Acrobatics of BQP

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    One can fix the randomness used by a randomized algorithm, but there is no analogous notion of fixing the quantumness used by a quantum algorithm. Underscoring this fundamental difference, we show that, in the black-box setting, the behavior of quantum polynomial-time (BQP\mathsf{BQP}) can be remarkably decoupled from that of classical complexity classes like NP\mathsf{NP}. Specifically: -There exists an oracle relative to which NPBQP⊄BQPPH\mathsf{NP^{BQP}}\not\subset\mathsf{BQP^{PH}}, resolving a 2005 problem of Fortnow. As a corollary, there exists an oracle relative to which P=NP\mathsf{P}=\mathsf{NP} but BQPQCMA\mathsf{BQP}\neq\mathsf{QCMA}. -Conversely, there exists an oracle relative to which BQPNP⊄PHBQP\mathsf{BQP^{NP}}\not\subset\mathsf{PH^{BQP}}. -Relative to a random oracle, PP=PostBQP\mathsf{PP}=\mathsf{PostBQP} is not contained in the "QMA\mathsf{QMA} hierarchy" QMAQMAQMA\mathsf{QMA}^{\mathsf{QMA}^{\mathsf{QMA}^{\cdots}}}. -Relative to a random oracle, Σk+1P⊄BQPΣkP\mathsf{\Sigma}_{k+1}^\mathsf{P}\not\subset\mathsf{BQP}^{\mathsf{\Sigma}_{k}^\mathsf{P}} for every kk. -There exists an oracle relative to which BQP=P#P\mathsf{BQP}=\mathsf{P^{\# P}} and yet PH\mathsf{PH} is infinite. -There exists an oracle relative to which P=NPBQP=P#P\mathsf{P}=\mathsf{NP}\neq\mathsf{BQP}=\mathsf{P^{\# P}}. To achieve these results, we build on the 2018 achievement by Raz and Tal of an oracle relative to which BQP⊄PH\mathsf{BQP}\not \subset \mathsf{PH}, and associated results about the Forrelation problem. We also introduce new tools that might be of independent interest. These include a "quantum-aware" version of the random restriction method, a concentration theorem for the block sensitivity of AC0\mathsf{AC^0} circuits, and a (provable) analogue of the Aaronson-Ambainis Conjecture for sparse oracles.Comment: 63 pages. V2: various writing improvement
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