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A Unifying Hierarchy of Valuations with Complements and Substitutes [article]

Uriel Feige, Michal Feldman, Nicole Immorlica, Rani Izsak, Brendan Lucier, Vasilis Syrgkanis
2014 arXiv   pre-print
Levels of the hierarchy correspond to the degree of complementarity in a given function.  ...  One shows that the maximum welfare problem can be approximated within a ratio of k+1 if all players hold valuation functions in MPH-k.  ...  Abraham, Babaioff, Dughmi, and Roughgarden [1] consider the hierarchy of PH-k valuation functions, as already defined, (which are obviously contained in MPH-k) that allows only complements but no substitutes  ... 
arXiv:1408.1211v1 fatcat:l3kdlripujgyrcgw5cj2hbf5iu

Automatic inference of abstract type behavior

Mihai Balint
2010 Proceedings of the IEEE/ACM international conference on Automated software engineering - ASE '10  
The inferred automaton is simulated by the behavior of each subtype and can be used for safe hierarchy extension, verification of new hierarchy clients, and emphasis of LSP non-compliant methods.  ...  legal usage of abstract supertypes and ensures the behavioral subtyping relation as defined by the Liskov Substitution Principle (LSP).  ...  We also acknowledge Petru Mihacea, Daniel Ratiu and Casandra Holotescu for their suggestions and editorial advice.  ... 
doi:10.1145/1858996.1859097 dblp:conf/kbse/Balint10 fatcat:gowbnqlhobgbpenzn54ks6bm7m

Why Prices Need Algorithms

Tim Roughgarden, Inbal Talgam-Cohen
2015 Proceedings of the Sixteenth ACM Conference on Economics and Computation - EC '15  
This paper shows that the existence of pricing equilibria is inextricably connected to the computational complexity of related optimization problems: demand oracles, revenue-maximization, and welfare-maximization  ...  This relationship implies, under suitable complexity assumptions, a host of impossibility results.  ...  Vasilis Gkatzelis of Stanford University for multiple discussions from which we greatly benefited.  ... 
doi:10.1145/2764468.2764515 dblp:conf/sigecom/RoughgardenT15 fatcat:64fkp5vpdffrzhm7zhjzauidze

Why prices need algorithms

Tim Roughgarden, Inbal Talgam-Cohen
2016 ACM SIGecom Exchanges  
This paper shows that the existence of pricing equilibria is inextricably connected to the computational complexity of related optimization problems: demand oracles, revenue-maximization, and welfare-maximization  ...  This relationship implies, under suitable complexity assumptions, a host of impossibility results.  ...  Vasilis Gkatzelis of Stanford University for multiple discussions from which we greatly benefited.  ... 
doi:10.1145/2904104.2904109 fatcat:yrqqsffgczattghmfyvkm4is5i

Are Gross Substitutes a Substitute for Submodular Valuations? [article]

Shahar Dobzinski and Uriel Feige and Michal Feldman and Renato Paes Leme
2022 arXiv   pre-print
GS belongs to the hierarchy of complement free valuations introduced by Lehmann, Lehmann and Nisan, along with other prominent classes: GS ⊊ Submodular ⊊ XOS ⊊ Subadditive.  ...  The class of gross substitutes (GS) set functions plays a central role in Economics and Computer Science.  ...  Acknowledgements In a previous version of this paper, Lemma 3.6 was proved using a computer assisted proof.  ... 
arXiv:2102.13343v3 fatcat:ypimdflalrcy3jxhjiea2i3aee

When Are Welfare Guarantees Robust? [article]

Tim Roughgarden and Inbal Talgam-Cohen and Jan Vondrák
2016 arXiv   pre-print
We show that for valuations that pointwise approximate a gross substitutes valuation (in fact even a linear valuation), optimal social welfare cannot be approximated to within a subpolynomial factor and  ...  to various subclasses of gross substitutes valuations.  ...  More generally, in settings with both substitutes and complements, the folklore belief in the field is that simple auction formats should produce allocations with near-optimal social welfare if and only  ... 
arXiv:1608.02402v1 fatcat:cbb24qspmbg7bkyifgo5p5izs4

Designing user-adapted interfaces

A. Savidis, A. Paramythis, D. Akoumianakis, C. Stephanidis
1997 Proceedings of the conference on Designing interactive systems processes, practices, methods, and techniques - DIS '97  
The unified design method is targeted towards the organization of alternative design artifacts into a single representation structure.  ...  Relationships among alternative artifacts in user-adapted design, such as exclusion, compatibility, augmentation and substitution, need to be explicitly represented.  ...  The complemental role of adaptability and adaptivity approaches is illustrated within Figure 7 .  ... 
doi:10.1145/263552.263636 dblp:conf/ACMdis/SavidisPAS97 fatcat:wlkrjogejbcytatcpqolwcjkfe

Algebraic modal correspondence: Sahlqvist and beyond [article]

Willem Conradie and Alessandra Palmigiano and Sumit Sourabh
2016 arXiv   pre-print
a class of formulas laying outside the Sahlqvist class proper.  ...  However, it provides the underlying motivation and basic intuitions for the recent developments in the Sahlqvist theory of nonclassical logics, which compose the so-called unified correspondence theory  ...  and the intersection of the complements of singletons of its non-elements, and the fact that the meaning function associated with ϕ ′ is 1-additive.  ... 
arXiv:1606.06881v1 fatcat:hpwcoofjlne2lhjbuclntgkkxi

Approximately Optimal Mechanism Design [article]

Tim Roughgarden, Inbal Talgam-Cohen
2020 arXiv   pre-print
Optimal mechanism design enjoys a beautiful and well-developed theory, and also a number of killer applications.  ...  This survey reviews several common issues with optimal mechanisms, including exorbitant communication, computation, and informational requirements; and it presents several examples demonstrating that passing  ...  Acknowledgments The first author is supported in part by NSF Award CCF-1813188 and a Guggenheim Fellowship, and performed this work in part while visiting the London School of Economics.  ... 
arXiv:1812.11896v2 fatcat:5q5l34g65jf7beogswtr7nevta

XMG: eXtensible MetaGrammar

Benoît Crabbé, Denys Duchier, Claire Gardent, Joseph Roux, Yannick Parmentier
2013 Computational Linguistics  
This illustrates both how XMG facilitates the modeling of the tree fragment hierarchies required to specify tree-based grammars and of a syntax/semantics interface between semantic representations and  ...  To further illustrate the declarativity, notational expressivity, and extensibility of XMG, we describe the methodology used to specify an FB-LTAG for French augmented with a Computational Linguistics  ...  On substitution, the top features of the substitution node are unified with the top features of the root node of the tree being substituted in.  ... 
doi:10.1162/coli_a_00144 fatcat:ux2jdlblb5hobgjgb6ruqsyadi

Fixed point characterization of infinite behavior of finite-state systems

Damian Niwiński
1997 Theoretical Computer Science  
A tight correspondence is established between a hierarchy of Rabin indices of automata and a hierarchy induced by alternation of the least and greatest fixed point operators.  ...  It is shown that, in the powerset algebra of trees constructed from a set of functional symbols, the fixed point hierarchy is infinite unless all the symbols are unary (i.e. trees are words).  ...  I am also indebted to the referees for corrections and helpful comments, and to Igor Walukiewicz for his critical remarks on the preliminary version of this paper.  ... 
doi:10.1016/s0304-3975(97)00039-x fatcat:qeygcpsdarelljxucv7a6xshp4

Improved Prophet Inequalities for Combinatorial Welfare Maximization with (Approximately) Subadditive Agents

Hanrui Zhang, Peter Sanders, Grzegorz Herman, Fabrizio Grandoni
2020 European Symposium on Algorithms  
, (2) an O(D log m / log log m)-competitive prophet inequality for D-approximately subadditive agents, where D ∈ {1, ... , m-1} measures the maximum number of items that complement each other, and (3)  ...  We give a framework for designing prophet inequalities for combinatorial welfare maximization.  ...  We begin our investigation with subadditive (also known as complement-free) agents, who regard items only as substitutes but not complements to each other.  ... 
doi:10.4230/lipics.esa.2020.82 dblp:conf/esa/Zhang20 fatcat:4urerxq725d2voqx2a22f6gd6e

Rules with parameters in modal logic II [article]

Emil Jeřábek
2020 arXiv   pre-print
We analyze the computational complexity of admissibility and unifiability with parameters in transitive modal logics.  ...  In addition to the main case where arbitrary parameters are allowed, we consider restricted problems with the number of parameters bounded by a constant, and the parameter-free case.  ...  The Institute of Mathematics of the Czech Academy of Sciences is supported by RVO: 67985840.  ... 
arXiv:1905.13157v2 fatcat:e7yxsy5cebf6vebruezshk4eum

The μ-Calculus Alternation Hierarchy Collapses over Structures with Restricted Connectivity

Julian Gutierrez, Felix Klaedtke, Martin Lange
2012 Electronic Proceedings in Theoretical Computer Science  
infinite nested words and finite graphs with feedback vertex sets of a bounded size.  ...  It is known that the alternation hierarchy of least and greatest fixpoint operators in the mu-calculus is strict.  ...  Julian Gutierrez acknowledges with gratitude the support of EPSRC grant 'Solving Parity Games and Mu-Calculi' and ERC Advanced grant ECSYM.  ... 
doi:10.4204/eptcs.96.9 fatcat:ilfyzzs5fjc5xdaqufboz3pdk4

Simultaneous auctions are (almost) efficient

Michal Feldman, Hu Fu, Nick Gravin, Brendan Lucier
2013 Proceedings of the 45th annual ACM symposium on Symposium on theory of computing - STOC '13  
We introduce a new proof technique and use it to resolve both of these gaps in a unified way.  ...  We study the efficiency of Bayesian Nash equilibrium (BNE) outcomes of simultaneous first-and second-price auctions when bidders have complement-free (a.k.a. subadditive) valuations.  ...  The class of subadditive functions strictly includes a hierarchy of more restrictive complement-free functions such as submodular and gross substitute functions (see 14 for definitions and discussions)  ... 
doi:10.1145/2488608.2488634 dblp:conf/stoc/FeldmanFGL13 fatcat:b4kuo3rib5dghe4gcvwmd5nxea
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