Lecture Notes in Computer Science 9541

Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan van Leeuwen

Editorial Board David Hutchison Lancaster University, Lancaster, UK Takeo Kanade Carnegie Mellon University, Pittsburgh, PA, USA Josef Kittler University of Surrey, Guildford, UK Jon M. Kleinberg Cornell University, Ithaca, NY, USA Friedemann Mattern ETH Zurich, Zürich, Switzerland John C. Mitchell Stanford University, Stanford, CA, USA Moni Naor Weizmann Institute of Science, Rehovot, Israel C. Pandu Rangan Indian Institute of Technology, Madras, India Bernhard Steffen TU Dortmund University, Dortmund, Germany Demetri Terzopoulos University of California, Los Angeles, CA, USA Doug Tygar University of California, Berkeley, CA, USA Gerhard Weikum Max Planck Institute for Informatics, Saarbrücken, Germany More information about this series at http://www.springer.com/series/7407 Mohammad Taghi Hajiaghayi Mohammad Reza Mousavi (Eds.)

Topics in Theoretical Computer Science

The First IFIP WG 1.8 International Conference, TTCS 2015 Tehran, Iran, August 26–28, 2015 Revised Selected Papers

123 Editors Mohammad Taghi Hajiaghayi Mohammad Reza Mousavi Computer Science Department Centre for Research on Embedded Systems University of Maryland Halmstad University College Park, MD Halmstad USA Sweden

ISSN 0302-9743 ISSN 1611-3349 (electronic) Lecture Notes in Computer Science ISBN 978-3-319-28677-8 ISBN 978-3-319-28678-5 (eBook) DOI 10.1007/978-3-319-28678-5

Library of Congress Control Number: 2015958862

LNCS Sublibrary: SL1 – Theoretical Computer Science and General Issues

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This Springer imprint is published by SpringerNature The registered company is Springer International Publishing AG Switzerland Preface

Welcome to the proceedings of the First IFIP International Conference on Topics in Theoretical Computer Science (TTCS 2015)! This volume contains the revised papers presented at TTCS 2015. The conference was held during August 26–28, 2015, at the Institute for Research in Fundamental Sciences (IPM), Tehran, Iran. For this first edition of TTCS, we received 48 submissions from 12 different countries. An international Program Committee comprising 45 leading scientists from 14 countries reviewed the papers thoroughly providing on average five review reports for each paper. We ended up accepting 11 submissions, which translates into less than 23 % of all submissions. This means that the process was highly selective and only very high quality papers were accepted. The program also included three invited talks by the following world-renowned computer scientists: – Prof. Anuj Dawar, Cambridge University, UK, – Prof. Michael Fellows, Charles Darwin University, Australia, and – Dr. Mehrnoosh Sadrzadeh, Queen Mary University of London, UK. These invited lectures are also represented either by an abstract or by a full paper in the proceedings. Additionally, the program featured four talks in the PhD Forum, which are not included in the proceedings. We thank IPM, and in particular the Organizing Committee, for having provided various facilities and for their generous support. We believe that, thanks to their help, the conference organization was run smoothly and conveniently. We are also grateful to our program committee for their professional and hard work in providing expert review reports and thorough discussions leading to a very interesting and strong pro- gram. We also acknowledge the excellent facilities provided by the EasyChair system, which have been crucial in managing the process of submission, selection, revision, and publication of the manuscripts included in the proceedings.

November 2015 Mohammad Taghi Hajiaghayi Mohammad Reza Mousavi Organization

Program Committee

Mohammad A. Abam Sharif University of Technology, Tehran, Iran Saeed Akbari Sharif University of Technology, Tehran, Iran Saeed Alaei Cornell University, USA Farhad Arbab CWI and Leiden University, The Netherlands S. Arun-Kumar Indian Institue of Technology Delhi, India Mohammad H. Bateni Google Research, USA Salman Beigi IPM, Iran Ilaria Castellani Inria Sophia Antipolis Mediterranee, France Dave Clarke Uppsala University, Sweden Pieter Cuijpers Eindhoven University of Technology, The Netherlands Amir Daneshgar Sharif University of Technology, Iran Fedor Fomin University of Bergen, Norway Fatemeh Ghassemi University of Tehran, Iran Ali Ghodsi University of Waterloo, Canada Mohammad Ghodsi Sharif University of Technology, Iran Mohammad T. Hajiaghayi University of Maryland, USA Ichiro Hasuo University of Tokyo, Japan Matthew Hennessy Trinity College Dublin, Ireland Nicole Immorlica Microsoft Research, USA Mohammad M. Jaghoori AMC of University of Amsterdam, The Netherlands Amin Karbasi Yale University, USA Jeroen Keiren Open University Netherlands, The Netherlands Amit Kumar Indian Institute of Technology Delhi, India Bas Luttik Eindhoven University of Technology, The Netherlands Mohammad Mahdian Google Research, USA Hamid Mahini University of Maryland, USA Mohammad Mahmoody University of Virginia, USA Jose Meseguer University of Illinois, USA Vahab Mirrokni Google Research, USA Bojan Mohar Simon Fraser University, Canada Morteza Monemizadeh Frankfurt University, Germany Lary Moss Indiana University, USA Mohammad R. Mousavi Halmstad University, Sweden Shayan Oveisgharan University of Washington, USA Jun Pang University of Luxembourg, Luxembourg Debmalya Panigrahi Duke University, USA Jorg Sack Carleton University, Canada VIII Organization

Gerardo Schneider Chalmers — University of Gothenburg, Sweden Mohit Singh Microsoft Research, USA Marjan Sirjani Reykjavik University, Reykjavik, Iceland Dimitrios M. Thilikos CNRS, France and University of Athens, Greece S. Venkatasubramanian University of Utah, USA Walter Vogler Augsburg University, Germany Jan Vondrak IBM Almaden Research Center, USA Tim Willemse Eindhoven University of Technology, The Netherlands

Additional Reviewers

Abbasi Zadeh, Sepehr Fox, Kyle Sabahi Kaviani, Zeynab Alégroth, Emil Gacs, Peter Schmaltz, Julien Baharifard, Fatemeh Haney, Samuel Shameli, Seyed Ali Banijamali, Ershad Homapour, Hamid Shariatpanahi, Beohar, Harsh Jonker, Hugo Seyed Pooya Bujtor, Ferenc Kell, Nathaniel Sidorova, Natalia Chen, Lin Khamespanah, Ehsan Suykens, Johan Clairambault, Pierre Krčál, Jan Tichy, Matthias Corby, Olivier Langetepe, Elmar Visser, Arnoud Damaschke, Peter Melliès, Paul-André Volpato, Michele Deng, Yuxin Nemati, Soheil Abstracts of Invited Talks New Directions in Parameterized Algorithmics

Michael Fellows

Charles Darwin University, Australia

The talk will review some basics of the field, and then focus on some new directions in parameterized/multivariate algorithmics. These include: • The systematic deconstruction of NP-hardness results for problems unrealistically legislated with real numbers, by parameterizing on the size of a relevant finitized arithmetic system. • Fresh paradigms for deploying parameterization to FPT-turbocharge heuristics (such as greedy algorithms) and other subroutines of current approaches in practical computing for NP-hard problems. • Aggressive aggregate parameterization including generative parameterization of typical instances of hard problems, building on and deepening the parameter ecology program. • Parameterization in the context of dynamic problems where inputs change (a bit) and solutions need to be changed (a bit). • The axiomatization of groovy FPT, where canonically structured kernelization is canonically convertible to: P-time approximation algorithms; inductive gradients for local search; sharper turbocharging for greedy algorithms, local search and genetic recombination heuristics — opening up a whole new level of groovy lower bound questions, such as the existence of groovy polynomial kernels. (Recent results show that some FPT parameterized problems admit polynomial kernels, but do not admit groovy polynomial kernelization unless P = NP.) • The accidental origins of parameterized complexity in graph minor theory (well quasi-ordering + FPT order tests) is a general phenomenon: it has recently been shown that a parameterized problem is FPT if and only if this can be derived from a well-behaved WQO context. Where this leads is entirely open. Distributional Sentence Entailment Using Density Matrices

Esma Balkr1, Mehrnoosh Sadrzadeh1, and Bob Coecke2

1 Queen Mary University of London 2 University of Oxford

Abstract. Categorical compositional distributional model of Clark, Coecke, and Sadrzadeh suggests a way to combine grammatical composition of the formal, type logical models with the corpus based, empirical word representations of distributional semantics. This paper contributes to the project by expanding the model to also capture entailment relations. This is achieved by extending the representations of words from points in meaning space to density operators, which are probability distributions on the subspaces of the space. A symmetric measure of similarity and an asymmetric measure of entailment is defined, where lexical entailment is measured using von Neumann entropy, the quantum variant of Kullback-Leibler divergence. Lexical entailment, combined with the composition map on word representations, provides a method to obtain entail- ment relations on the level of sentences. Truth theoretic and corpus-based examples are provided. On Symmetric and Choiceless Computation

Anuj Dawar

University of Cambridge Computer Laboratory, William Gates Building, J.J. Thomson Avenue, Cambridge, CB3 0FD, UK [email protected]

Formal models of computation such as Turing machines are usually defined as per- forming operations on strings of symbols. Indeed, for most purposes, it suffices to consider strings over a two-letter alphabet {0, 1}. Decision problems are defined as sets of strings, and complexity classes as sets of decision problems. However, many natural algorithms are described on more abstract structure (such as graphs) because this is the natural level of abstraction at which to describe the problem being solved. Of course, we know that the abstract structures can be ultimately represented as strings (and, indeed, have to be in actual computational devices), but the representation comes at a cost. The same abstract structure may have many different string representations and the implementation of the algorithm may break the intended abstraction. Research in the area of finite model theory and descriptive complexity (see [11, 13]) has, over the years, developed a number of techniques of describing algorithms and complexity classes directly on classes of relational structures, rather than strings. Along with this, many methods of proving inexpressiblity results have been shown, often described in terms of games. A key question that has been the focus of this research effort is whether the complexity class P admits a descriptive characterisation (see [10, Chap. 11]). A recent paper [1] ties some of the logics studied in finite model theory to natural circuit complexity classes, and shows thereby that inexpressibility results obtained in finite model theory can be understood as lower bound results on such classes. In this presentation, I develop the methods for proving lower bound results in the form of combinatorial arguments on circuits, without reference to logical definability. The present abstract gives a brief account of the results and methods. Contents

Distributional Sentence Entailment Using Density Matrices ...... 1 Esma Balkir, Mehrnoosh Sadrzadeh, and Bob Coecke

On Symmetric and Choiceless Computation ...... 23 Anuj Dawar

Robots’ Cooperation for Finding a Target in Streets ...... 30 Mohammad Abouei Mehrizi, Mohammad Ghodsi, and Azadeh Tabatabaei

Some Properties of Continuous Yao Graph...... 44 Davood Bakhshesh and Mohammad Farshi

Plane Geodesic Spanning Trees, Hamiltonian Cycles, and Perfect Matchings in a Simple Polygon ...... 56 Ahmad Biniaz, Prosenjit Bose, Anil Maheshwari, and Michiel Smid

Visibility Graphs of Anchor Polygons ...... 72 Hossein Boomari and Alireza Zarei

Automating the Verification of Realtime Observers Using Probes and the Modal mu-calculus ...... 90 Silvano Dal Zilio and Bernard Berthomieu

Minimizing Walking Length in Map Matching ...... 105 Amin Gheibi, Anil Maheshwari, and Jörg-Rüdiger Sack

Rainbow Domination and Related Problems on Some Classes of Perfect Graphs ...... 121 Wing-Kai Hon, Ton Kloks, Hsiang-Hsuan Liu, and Hung-Lung Wang

Efficient Computation of Generalized Ising Polynomials on Graphs with Fixed Clique-Width ...... 135 Tomer Kotek and Johann A. Makowsky

Infinite Subgame Perfect Equilibrium in the Hausdorff Difference Hierarchy ...... 147 Stéphane Le Roux

Deterministic Algorithm for 1-Median 1-Center Two-Objective Optimization Problem ...... 164 Vahid Roostapour, Iman Kiarazm, and Mansoor Davoodi

Author Index ...... 179