[{"alternative_title":["IST Austria Technical Report"],"day":"19","has_accepted_license":"1","oa":1,"related_material":{"record":[{"id":"5421","relation":"earlier_version","status":"public"},{"id":"5440","relation":"later_version","status":"public"}]},"status":"public","file":[{"file_name":"IST-2015-323-v1+1_main.pdf","content_type":"application/pdf","creator":"system","file_size":576347,"file_id":"5519","checksum":"546c1b291d545e7b24aaaf4199dac671","access_level":"open_access","date_updated":"2020-07-14T12:46:53Z","relation":"main_file","date_created":"2018-12-12T11:53:57Z"}],"page":"29","file_date_updated":"2020-07-14T12:46:53Z","oa_version":"Published Version","language":[{"iso":"eng"}],"citation":{"ieee":"K. Chatterjee, R. Ibsen-Jensen, and M. Nowak, *The complexity of evolutionary games on graphs*. IST Austria, 2015.","ista":"Chatterjee K, Ibsen-Jensen R, Nowak M. 2015. The complexity of evolutionary games on graphs, IST Austria, 29p.","apa":"Chatterjee, K., Ibsen-Jensen, R., & Nowak, M. (2015). *The complexity of evolutionary games on graphs*. IST Austria. https://doi.org/10.15479/AT:IST-2015-323-v1-1","ama":"Chatterjee K, Ibsen-Jensen R, Nowak M. *The Complexity of Evolutionary Games on Graphs*. IST Austria; 2015. doi:10.15479/AT:IST-2015-323-v1-1","mla":"Chatterjee, Krishnendu, et al. *The Complexity of Evolutionary Games on Graphs*. IST Austria, 2015, doi:10.15479/AT:IST-2015-323-v1-1.","short":"K. Chatterjee, R. Ibsen-Jensen, M. Nowak, The Complexity of Evolutionary Games on Graphs, IST Austria, 2015.","chicago":"Chatterjee, Krishnendu, Rasmus Ibsen-Jensen, and Martin Nowak. *The Complexity of Evolutionary Games on Graphs*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-323-v1-1."},"department":[{"_id":"KrCh"}],"author":[{"first_name":"Krishnendu","orcid":"0000-0002-4561-241X","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"},{"orcid":"0000-0003-4783-0389","full_name":"Ibsen-Jensen, Rasmus","last_name":"Ibsen-Jensen","id":"3B699956-F248-11E8-B48F-1D18A9856A87","first_name":"Rasmus"},{"first_name":"Martin","full_name":"Nowak, Martin","last_name":"Nowak"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","_id":"5432","date_updated":"2021-01-12T08:02:20Z","type":"technical_report","title":"The complexity of evolutionary games on graphs","date_created":"2018-12-12T11:39:18Z","pubrep_id":"323","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]},"year":"2015","publication_status":"published","doi":"10.15479/AT:IST-2015-323-v1-1","ddc":["005","576"],"date_published":"2015-02-19T00:00:00Z","abstract":[{"lang":"eng","text":"Evolution occurs in populations of reproducing individuals. The structure of the population affects the outcome of the evolutionary process. Evolutionary graph theory is a powerful approach to study this phenomenon. There are two graphs. The interaction graph specifies who interacts with whom in the context of evolution.The replacement graph specifies who competes with whom for reproduction. \r\nThe vertices of the two graphs are the same, and each vertex corresponds to an individual of the population. A key quantity is the fixation probability of a new mutant. It is defined as the probability that a newly introduced mutant (on a single vertex) generates a lineage of offspring which eventually takes over the entire population of resident individuals. The basic computational questions are as follows: (i) the qualitative question asks whether the fixation probability is positive; and (ii) the quantitative approximation question asks for an approximation of the fixation probability. \r\nOur main results are:\r\n(1) We show that the qualitative question is NP-complete and the quantitative approximation question is #P-hard in the special case when the interaction and the replacement graphs coincide and even with the restriction that the resident individuals do not reproduce (which corresponds to an invading population taking over an empty structure).\r\n(2) We show that in general the qualitative question is PSPACE-complete and the quantitative approximation question is PSPACE-hard and can be solved in exponential time.\r\n"}],"month":"02"},{"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Anonymous 1, Anonymous 2. *Optimal Cost Indefinite-Horizon Reachability in Goal DEC-POMDPs*. IST Austria; 2015.","apa":"Anonymous, 1, & Anonymous, 2. (2015). *Optimal cost indefinite-horizon reachability in goal DEC-POMDPs*. IST Austria.","mla":"Anonymous, 1, and 2 Anonymous. *Optimal Cost Indefinite-Horizon Reachability in Goal DEC-POMDPs*. IST Austria, 2015.","ieee":"1 Anonymous and 2 Anonymous, *Optimal cost indefinite-horizon reachability in goal DEC-POMDPs*. IST Austria, 2015.","ista":"Anonymous 1, Anonymous 2. 2015. Optimal cost indefinite-horizon reachability in goal DEC-POMDPs, IST Austria, 16p.","short":"1 Anonymous, 2 Anonymous, Optimal Cost Indefinite-Horizon Reachability in Goal DEC-POMDPs, IST Austria, 2015.","chicago":"Anonymous, 1, and 2 Anonymous. *Optimal Cost Indefinite-Horizon Reachability in Goal DEC-POMDPs*. IST Austria, 2015."},"author":[{"last_name":"Anonymous","full_name":"Anonymous, 1","first_name":"1"},{"full_name":"Anonymous, 2","last_name":"Anonymous","first_name":"2"}],"pubrep_id":"326","date_created":"2018-12-12T11:39:18Z","title":"Optimal cost indefinite-horizon reachability in goal DEC-POMDPs","_id":"5434","type":"technical_report","date_updated":"2020-07-14T23:04:59Z","file":[{"relation":"main_file","date_created":"2018-12-12T11:53:14Z","access_level":"open_access","date_updated":"2020-07-14T12:46:53Z","file_id":"5475","checksum":"8542fd0b10aed7811cd41077b8ccb632","content_type":"application/pdf","file_name":"IST-2015-326-v1+1_main.pdf","creator":"system","file_size":378162},{"file_id":"6317","checksum":"84c31c537bdaf7a91909f18d25d640ab","file_name":"IST-2015-326-v1+2_authors.txt","content_type":"text/plain","file_size":64,"creator":"dernst","relation":"main_file","date_created":"2019-04-16T13:00:33Z","access_level":"closed","date_updated":"2020-07-14T12:46:53Z"}],"status":"public","has_accepted_license":"1","oa":1,"day":"19","alternative_title":["IST Austria Technical Report"],"language":[{"iso":"eng"}],"oa_version":"Published Version","file_date_updated":"2020-07-14T12:46:53Z","page":"16","ddc":["000"],"month":"02","abstract":[{"lang":"eng","text":"DEC-POMDPs extend POMDPs to a multi-agent setting, where several agents operate in an uncertain environment independently to achieve a joint objective. DEC-POMDPs have been studied with finite-horizon and infinite-horizon discounted-sum objectives, and there exist solvers both for exact and approximate solutions. In this work we consider Goal-DEC-POMDPs, where given a set of target states, the objective is to ensure that the target set is reached with minimal cost. We consider the indefinite-horizon (infinite-horizon with either discounted-sum, or undiscounted-sum, where absorbing goal states have zero-cost) problem. We present a new method to solve the problem that extends methods for finite-horizon DEC- POMDPs and the RTDP-Bel approach for POMDPs. We present experimental results on several examples, and show our approach presents promising results."}],"date_published":"2015-02-19T00:00:00Z","publication_status":"published","year":"2015","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]}},{"publication_status":"published","publication_identifier":{"issn":["2664-1690"]},"publisher":"IST Austria","year":"2015","doi":"10.15479/AT:IST-2015-318-v2-1","ddc":["004"],"month":"02","date_published":"2015-02-23T00:00:00Z","abstract":[{"text":"We consider Markov decision processes (MDPs) with multiple limit-average (or mean-payoff) objectives. \r\nThere have been two different views: (i) the expectation semantics, where the goal is to optimize the expected mean-payoff objective, and (ii) the satisfaction semantics, where the goal is to maximize the probability of runs such that the mean-payoff value stays above a given vector. \r\nWe consider the problem where the goal is to optimize the expectation under the constraint that the satisfaction semantics is ensured, and thus consider a generalization that unifies the existing semantics. Our problem captures the notion of optimization with respect to strategies that are risk-averse (i.e., ensures certain probabilistic guarantee).\r\nOur main results are algorithms for the decision problem which are always polynomial in the size of the MDP.\r\nWe also show that an approximation of the Pareto-curve can be computed in time polynomial in the size of the MDP, and the approximation factor, but exponential in the number of dimensions. Finally, we present a complete characterization of the strategy complexity (in terms of memory bounds and randomization) required to solve our problem.","lang":"eng"}],"status":"public","related_material":{"record":[{"id":"5429","relation":"earlier_version","status":"public"},{"status":"public","id":"466","relation":"later_version"},{"id":"1657","relation":"later_version","status":"public"}]},"file":[{"date_created":"2018-12-12T11:54:03Z","relation":"main_file","date_updated":"2020-07-14T12:46:53Z","access_level":"open_access","checksum":"75284adec80baabdfe71ff9ebbc27445","file_id":"5525","creator":"system","file_size":717630,"file_name":"IST-2015-318-v2+1_main.pdf","content_type":"application/pdf"}],"day":"23","alternative_title":["IST Austria Technical Report"],"has_accepted_license":"1","oa":1,"oa_version":"Published Version","language":[{"iso":"eng"}],"page":"51","file_date_updated":"2020-07-14T12:46:53Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"orcid":"0000-0002-4561-241X","last_name":"Chatterjee","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","full_name":"Chatterjee, Krishnendu","first_name":"Krishnendu"},{"last_name":"Komarkova","full_name":"Komarkova, Zuzana","first_name":"Zuzana"},{"orcid":"0000-0002-8122-2881","last_name":"Kretinsky","id":"44CEF464-F248-11E8-B48F-1D18A9856A87","full_name":"Kretinsky, Jan","first_name":"Jan"}],"department":[{"_id":"KrCh"}],"citation":{"short":"K. Chatterjee, Z. Komarkova, J. Kretinsky, Unifying Two Views on Multiple Mean-Payoff Objectives in Markov Decision Processes, IST Austria, 2015.","chicago":"Chatterjee, Krishnendu, Zuzana Komarkova, and Jan Kretinsky. *Unifying Two Views on Multiple Mean-Payoff Objectives in Markov Decision Processes*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-318-v2-1.","ieee":"K. Chatterjee, Z. Komarkova, and J. Kretinsky, *Unifying two views on multiple mean-payoff objectives in Markov decision processes*. IST Austria, 2015.","ista":"Chatterjee K, Komarkova Z, Kretinsky J. 2015. Unifying two views on multiple mean-payoff objectives in Markov decision processes, IST Austria, 51p.","ama":"Chatterjee K, Komarkova Z, Kretinsky J. *Unifying Two Views on Multiple Mean-Payoff Objectives in Markov Decision Processes*. IST Austria; 2015. doi:10.15479/AT:IST-2015-318-v2-1","mla":"Chatterjee, Krishnendu, et al. *Unifying Two Views on Multiple Mean-Payoff Objectives in Markov Decision Processes*. IST Austria, 2015, doi:10.15479/AT:IST-2015-318-v2-1.","apa":"Chatterjee, K., Komarkova, Z., & Kretinsky, J. (2015). *Unifying two views on multiple mean-payoff objectives in Markov decision processes*. IST Austria. https://doi.org/10.15479/AT:IST-2015-318-v2-1"},"title":"Unifying two views on multiple mean-payoff objectives in Markov decision processes","date_created":"2018-12-12T11:39:19Z","pubrep_id":"327","type":"technical_report","_id":"5435","date_updated":"2021-01-12T08:02:15Z"},{"oa":1,"has_accepted_license":"1","day":"24","alternative_title":["IST Austria Technical Report"],"file":[{"file_id":"5541","checksum":"3c402f47d3669c28d04d1af405a08e3f","file_name":"IST-2015-170-v2+2_report.pdf","content_type":"application/pdf","file_size":569991,"creator":"system","relation":"main_file","date_created":"2018-12-12T11:54:19Z","access_level":"open_access","date_updated":"2020-07-14T12:46:54Z"}],"status":"public","related_material":{"record":[{"status":"public","relation":"earlier_version","id":"5415"},{"relation":"later_version","id":"467","status":"public"},{"relation":"later_version","id":"1656","status":"public"}]},"file_date_updated":"2020-07-14T12:46:54Z","page":"29","language":[{"iso":"eng"}],"oa_version":"Published Version","citation":{"short":"K. Chatterjee, T.A. Henzinger, J. Otop, Nested Weighted Automata, IST Austria, 2015.","chicago":"Chatterjee, Krishnendu, Thomas A Henzinger, and Jan Otop. *Nested Weighted Automata*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-170-v2-2.","ama":"Chatterjee K, Henzinger TA, Otop J. *Nested Weighted Automata*. IST Austria; 2015. doi:10.15479/AT:IST-2015-170-v2-2","apa":"Chatterjee, K., Henzinger, T. A., & Otop, J. (2015). *Nested weighted automata*. IST Austria. https://doi.org/10.15479/AT:IST-2015-170-v2-2","mla":"Chatterjee, Krishnendu, et al. *Nested Weighted Automata*. IST Austria, 2015, doi:10.15479/AT:IST-2015-170-v2-2.","ista":"Chatterjee K, Henzinger TA, Otop J. 2015. Nested weighted automata, IST Austria, 29p.","ieee":"K. Chatterjee, T. A. Henzinger, and J. Otop, *Nested weighted automata*. IST Austria, 2015."},"author":[{"orcid":"0000-0002-4561-241X","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","first_name":"Krishnendu"},{"first_name":"Thomas A","last_name":"Henzinger","full_name":"Henzinger, Thomas A","id":"40876CD8-F248-11E8-B48F-1D18A9856A87","orcid":"0000−0002−2985−7724"},{"last_name":"Otop","full_name":"Otop, Jan","id":"2FC5DA74-F248-11E8-B48F-1D18A9856A87","first_name":"Jan"}],"department":[{"_id":"KrCh"},{"_id":"ToHe"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","_id":"5436","type":"technical_report","date_updated":"2021-01-12T08:02:16Z","pubrep_id":"331","date_created":"2018-12-12T11:39:19Z","title":"Nested weighted automata","year":"2015","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]},"publication_status":"published","doi":"10.15479/AT:IST-2015-170-v2-2","ddc":["000"],"abstract":[{"lang":"eng","text":"Recently there has been a significant effort to handle quantitative properties in formal verification and synthesis. While weighted automata over finite and infinite words provide a natural and flexible framework to express quantitative properties, perhaps surprisingly, some basic system properties such as average response time cannot be expressed using weighted automata, nor in any other know decidable formalism. In this work, we introduce nested weighted automata as a natural extension of weighted automata which makes it possible to express important quantitative properties such as average response time.\r\nIn nested weighted automata, a master automaton spins off and collects results from weighted slave automata, each of which computes a quantity along a finite portion of an infinite word. Nested weighted automata can be viewed as the quantitative analogue of monitor automata, which are used in run-time verification. We establish an almost complete decidability picture for the basic decision problems about nested weighted automata, and illustrate their applicability in several domains. In particular, nested weighted automata can be used to decide average response time properties."}],"date_published":"2015-04-24T00:00:00Z","month":"04"},{"date_published":"2015-04-27T00:00:00Z","abstract":[{"lang":"eng","text":"We consider the core algorithmic problems related to verification of systems with respect to three classical quantitative properties, namely, the mean-payoff property, the ratio property, and the minimum initial credit for energy property. \r\nThe algorithmic problem given a graph and a quantitative property asks to compute the optimal value (the infimum value over all traces) from every node of the graph. We consider graphs with constant treewidth, and it is well-known that the control-flow graphs of most programs have constant treewidth. Let $n$ denote the number of nodes of a graph, $m$ the number of edges (for constant treewidth graphs $m=O(n)$) and $W$ the largest absolute value of the weights.\r\nOur main theoretical results are as follows.\r\nFirst, for constant treewidth graphs we present an algorithm that approximates the mean-payoff value within a multiplicative factor of $\\epsilon$ in time $O(n \\cdot \\log (n/\\epsilon))$ and linear space, as compared to the classical algorithms that require quadratic time. Second, for the ratio property we present an algorithm that for constant treewidth graphs works in time $O(n \\cdot \\log (|a\\cdot b|))=O(n\\cdot\\log (n\\cdot W))$, when the output is $\\frac{a}{b}$, as compared to the previously best known algorithm with running time $O(n^2 \\cdot \\log (n\\cdot W))$. Third, for the minimum initial credit problem we show that (i)~for general graphs the problem can be solved in $O(n^2\\cdot m)$ time and the associated decision problem can be solved in $O(n\\cdot m)$ time, improving the previous known $O(n^3\\cdot m\\cdot \\log (n\\cdot W))$ and $O(n^2 \\cdot m)$ bounds, respectively; and (ii)~for constant treewidth graphs we present an algorithm that requires $O(n\\cdot \\log n)$ time, improving the previous known $O(n^4 \\cdot \\log (n \\cdot W))$ bound.\r\nWe have implemented some of our algorithms and show that they present a significant speedup on standard benchmarks. "}],"month":"04","ddc":["000"],"doi":"10.15479/AT:IST-2015-330-v2-1","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]},"year":"2015","publication_status":"published","_id":"5437","type":"technical_report","date_updated":"2021-01-12T08:02:17Z","date_created":"2018-12-12T11:39:19Z","title":"Faster algorithms for quantitative verification in constant treewidth graphs","pubrep_id":"333","citation":{"chicago":"Chatterjee, Krishnendu, Rasmus Ibsen-Jensen, and Andreas Pavlogiannis. *Faster Algorithms for Quantitative Verification in Constant Treewidth Graphs*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-330-v2-1.","short":"K. Chatterjee, R. Ibsen-Jensen, A. Pavlogiannis, Faster Algorithms for Quantitative Verification in Constant Treewidth Graphs, IST Austria, 2015.","ista":"Chatterjee K, Ibsen-Jensen R, Pavlogiannis A. 2015. Faster algorithms for quantitative verification in constant treewidth graphs, IST Austria, 27p.","ieee":"K. Chatterjee, R. Ibsen-Jensen, and A. Pavlogiannis, *Faster algorithms for quantitative verification in constant treewidth graphs*. IST Austria, 2015.","mla":"Chatterjee, Krishnendu, et al. *Faster Algorithms for Quantitative Verification in Constant Treewidth Graphs*. IST Austria, 2015, doi:10.15479/AT:IST-2015-330-v2-1.","apa":"Chatterjee, K., Ibsen-Jensen, R., & Pavlogiannis, A. (2015). *Faster algorithms for quantitative verification in constant treewidth graphs*. IST Austria. https://doi.org/10.15479/AT:IST-2015-330-v2-1","ama":"Chatterjee K, Ibsen-Jensen R, Pavlogiannis A. *Faster Algorithms for Quantitative Verification in Constant Treewidth Graphs*. IST Austria; 2015. doi:10.15479/AT:IST-2015-330-v2-1"},"author":[{"orcid":"0000-0002-4561-241X","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","first_name":"Krishnendu"},{"orcid":"0000-0003-4783-0389","id":"3B699956-F248-11E8-B48F-1D18A9856A87","last_name":"Ibsen-Jensen","full_name":"Ibsen-Jensen, Rasmus","first_name":"Rasmus"},{"first_name":"Andreas","full_name":"Pavlogiannis, Andreas","id":"49704004-F248-11E8-B48F-1D18A9856A87","last_name":"Pavlogiannis","orcid":"0000-0002-8943-0722"}],"department":[{"_id":"KrCh"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","page":"27","file_date_updated":"2020-07-14T12:46:54Z","oa_version":"Published Version","language":[{"iso":"eng"}],"day":"27","alternative_title":["IST Austria Technical Report"],"oa":1,"has_accepted_license":"1","status":"public","related_material":{"record":[{"relation":"earlier_version","id":"5430","status":"public"},{"status":"public","relation":"later_version","id":"1607"}]},"file":[{"date_created":"2018-12-12T11:53:12Z","relation":"main_file","date_updated":"2020-07-14T12:46:54Z","access_level":"open_access","checksum":"f5917c20f84018b362d385c000a2e123","file_id":"5473","file_size":1072137,"creator":"system","content_type":"application/pdf","file_name":"IST-2015-330-v2+1_main.pdf"}]},{"file_date_updated":"2020-07-14T12:46:55Z","page":"15","language":[{"iso":"eng"}],"oa_version":"Published Version","oa":1,"has_accepted_license":"1","alternative_title":["IST Austria Technical Report"],"day":"05","file":[{"date_created":"2018-12-12T11:53:56Z","relation":"main_file","date_updated":"2020-07-14T12:46:55Z","access_level":"open_access","checksum":"8a5f2d77560e552af87eb1982437a43b","file_id":"5518","creator":"system","file_size":422573,"file_name":"IST-2015-334-v1+1_report.pdf","content_type":"application/pdf"}],"related_material":{"record":[{"status":"public","relation":"later_version","id":"465"},{"status":"public","relation":"later_version","id":"1610"}]},"status":"public","date_updated":"2021-01-12T08:02:18Z","_id":"5438","type":"technical_report","pubrep_id":"334","title":"Edit distance for pushdown automata","date_created":"2018-12-12T11:39:20Z","author":[{"orcid":"0000-0002-4561-241X","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","first_name":"Krishnendu"},{"orcid":"0000−0002−2985−7724","full_name":"Henzinger, Thomas A","last_name":"Henzinger","id":"40876CD8-F248-11E8-B48F-1D18A9856A87","first_name":"Thomas A"},{"orcid":"0000-0003-4783-0389","id":"3B699956-F248-11E8-B48F-1D18A9856A87","last_name":"Ibsen-Jensen","full_name":"Ibsen-Jensen, Rasmus","first_name":"Rasmus"},{"first_name":"Jan","full_name":"Otop, Jan","last_name":"Otop","id":"2FC5DA74-F248-11E8-B48F-1D18A9856A87"}],"citation":{"ista":"Chatterjee K, Henzinger TA, Ibsen-Jensen R, Otop J. 2015. Edit distance for pushdown automata, IST Austria, 15p.","ieee":"K. Chatterjee, T. A. Henzinger, R. Ibsen-Jensen, and J. Otop, *Edit distance for pushdown automata*. IST Austria, 2015.","mla":"Chatterjee, Krishnendu, et al. *Edit Distance for Pushdown Automata*. IST Austria, 2015, doi:10.15479/AT:IST-2015-334-v1-1.","apa":"Chatterjee, K., Henzinger, T. A., Ibsen-Jensen, R., & Otop, J. (2015). *Edit distance for pushdown automata*. IST Austria. https://doi.org/10.15479/AT:IST-2015-334-v1-1","ama":"Chatterjee K, Henzinger TA, Ibsen-Jensen R, Otop J. *Edit Distance for Pushdown Automata*. IST Austria; 2015. doi:10.15479/AT:IST-2015-334-v1-1","chicago":"Chatterjee, Krishnendu, Thomas A Henzinger, Rasmus Ibsen-Jensen, and Jan Otop. *Edit Distance for Pushdown Automata*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-334-v1-1.","short":"K. Chatterjee, T.A. Henzinger, R. Ibsen-Jensen, J. Otop, Edit Distance for Pushdown Automata, IST Austria, 2015."},"department":[{"_id":"KrCh"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","doi":"10.15479/AT:IST-2015-334-v1-1","year":"2015","publication_identifier":{"issn":["2664-1690"]},"publisher":"IST Austria","publication_status":"published","abstract":[{"text":"The edit distance between two words w1, w2 is the minimal number of word operations (letter insertions, deletions, and substitutions) necessary to transform w1 to w2. The edit distance generalizes to languages L1, L2, where the edit distance is the minimal number k such that for every word from L1 there exists a word in L2 with edit distance at most k. We study the edit distance computation problem between pushdown automata and their subclasses.\r\nThe problem of computing edit distance to a pushdown automaton is undecidable, and in practice, the interesting question is to compute the edit distance from a pushdown automaton (the implementation, a standard model for programs with recursion) to a regular language (the specification). In this work, we present a complete picture of decidability and complexity for deciding whether, for a given threshold k, the edit distance from a pushdown automaton to a finite automaton is at most k. ","lang":"eng"}],"date_published":"2015-05-05T00:00:00Z","month":"05","ddc":["004"]},{"doi":"10.15479/AT:IST-2015-335-v1-1","publication_status":"published","publication_identifier":{"issn":["2664-1690"]},"publisher":"IST Austria","year":"2015","month":"05","date_published":"2015-05-18T00:00:00Z","abstract":[{"text":"The target discounted-sum problem is the following: Given a rational discount factor 0 < λ < 1 and three rational values a, b, and t, does there exist a finite or an infinite sequence w ε(a, b)∗ or w ε(a, b)w, such that Σ|w| i=0 w(i)λi equals t? The problem turns out to relate to many fields of mathematics and computer science, and its decidability question is surprisingly hard to solve. We solve the finite version of the problem, and show the hardness of the infinite version, linking it to various areas and open problems in mathematics and computer science: β-expansions, discounted-sum automata, piecewise affine maps, and generalizations of the Cantor set. We provide some partial results to the infinite version, among which are solutions to its restriction to eventually-periodic sequences and to the cases that λ λ 1/2 or λ = 1/n, for every n ε N. We use our results for solving some open problems on discounted-sum automata, among which are the exact-value problem for nondeterministic automata over finite words and the universality and inclusion problems for functional automata. ","lang":"eng"}],"ddc":["004","512","513"],"oa_version":"Published Version","language":[{"iso":"eng"}],"page":"20","file_date_updated":"2020-07-14T12:46:55Z","status":"public","related_material":{"record":[{"status":"public","relation":"later_version","id":"1659"}]},"file":[{"file_id":"5517","checksum":"40405907aa012acece1bc26cf0be554d","content_type":"application/pdf","file_name":"IST-2015-335-v1+1_report.pdf","file_size":589619,"creator":"system","relation":"main_file","date_created":"2018-12-12T11:53:55Z","access_level":"open_access","date_updated":"2020-07-14T12:46:55Z"}],"day":"18","alternative_title":["IST Austria Technical Report"],"has_accepted_license":"1","oa":1,"title":"The target discounted-sum problem","date_created":"2018-12-12T11:39:20Z","pubrep_id":"335","_id":"5439","date_updated":"2021-01-12T08:02:19Z","type":"technical_report","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"short":"U. Boker, T.A. Henzinger, J. Otop, The Target Discounted-Sum Problem, IST Austria, 2015.","chicago":"Boker, Udi, Thomas A Henzinger, and Jan Otop. *The Target Discounted-Sum Problem*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-335-v1-1.","mla":"Boker, Udi, et al. *The Target Discounted-Sum Problem*. IST Austria, 2015, doi:10.15479/AT:IST-2015-335-v1-1.","apa":"Boker, U., Henzinger, T. A., & Otop, J. (2015). *The target discounted-sum problem*. IST Austria. https://doi.org/10.15479/AT:IST-2015-335-v1-1","ama":"Boker U, Henzinger TA, Otop J. *The Target Discounted-Sum Problem*. IST Austria; 2015. doi:10.15479/AT:IST-2015-335-v1-1","ieee":"U. Boker, T. A. Henzinger, and J. Otop, *The target discounted-sum problem*. IST Austria, 2015.","ista":"Boker U, Henzinger TA, Otop J. 2015. The target discounted-sum problem, IST Austria, 20p."},"department":[{"_id":"ToHe"}],"author":[{"first_name":"Udi","id":"31E297B6-F248-11E8-B48F-1D18A9856A87","full_name":"Boker, Udi","last_name":"Boker"},{"first_name":"Thomas A","orcid":"0000−0002−2985−7724","last_name":"Henzinger","full_name":"Henzinger, Thomas A","id":"40876CD8-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Jan","full_name":"Otop, Jan","last_name":"Otop","id":"2FC5DA74-F248-11E8-B48F-1D18A9856A87"}]},{"publication_status":"published","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]},"year":"2015","doi":"10.15479/AT:IST-2015-323-v2-2","ddc":["005","576"],"month":"06","date_published":"2015-06-16T00:00:00Z","abstract":[{"lang":"eng","text":"Evolution occurs in populations of reproducing individuals. The structure of the population affects the outcome of the evolutionary process. Evolutionary graph theory is a powerful approach to study this phenomenon. There are two graphs. The interaction graph specifies who interacts with whom for payoff in the context of evolution. The replacement graph specifies who competes with whom for reproduction. The vertices of the two graphs are the same, and each vertex corresponds to an individual of the population. The fitness (or the reproductive rate) is a non-negative number, and depends on the payoff. A key quantity is the fixation probability of a new mutant. It is defined as the probability that a newly introduced mutant (on a single vertex) generates a lineage of offspring which eventually takes over the entire population of resident individuals. The basic computational questions are as follows: (i) the qualitative question asks whether the fixation probability is positive; and (ii) the quantitative approximation question asks for an approximation of the fixation probability. Our main results are as follows: First, we consider a special case of the general problem, where the residents do not reproduce. We show that the qualitative question is NP-complete, and the quantitative approximation question is #P-complete, and the hardness results hold even in the special case where the interaction and the replacement graphs coincide. Second, we show that in general both the qualitative and the quantitative approximation questions are PSPACE-complete. The PSPACE-hardness result for quantitative approximation holds even when the fitness is always positive."}],"status":"public","related_material":{"record":[{"relation":"earlier_version","id":"5421","status":"public"},{"relation":"earlier_version","id":"5432","status":"public"}]},"file":[{"date_updated":"2020-07-14T12:46:56Z","access_level":"open_access","date_created":"2018-12-12T11:53:23Z","relation":"main_file","file_size":466161,"creator":"system","file_name":"IST-2015-323-v2+2_main.pdf","content_type":"application/pdf","checksum":"66aace7d367032af97c15e35c9be9636","file_id":"5484"}],"day":"16","alternative_title":["IST Austria Technical Report"],"has_accepted_license":"1","oa":1,"oa_version":"Published Version","language":[{"iso":"eng"}],"page":"18","file_date_updated":"2020-07-14T12:46:56Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"short":"K. Chatterjee, R. Ibsen-Jensen, M. Nowak, The Complexity of Evolutionary Games on Graphs, IST Austria, 2015.","chicago":"Chatterjee, Krishnendu, Rasmus Ibsen-Jensen, and Martin Nowak. *The Complexity of Evolutionary Games on Graphs*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-323-v2-2.","ieee":"K. Chatterjee, R. Ibsen-Jensen, and M. Nowak, *The complexity of evolutionary games on graphs*. IST Austria, 2015.","ista":"Chatterjee K, Ibsen-Jensen R, Nowak M. 2015. The complexity of evolutionary games on graphs, IST Austria, 18p.","apa":"Chatterjee, K., Ibsen-Jensen, R., & Nowak, M. (2015). *The complexity of evolutionary games on graphs*. IST Austria. https://doi.org/10.15479/AT:IST-2015-323-v2-2","mla":"Chatterjee, Krishnendu, et al. *The Complexity of Evolutionary Games on Graphs*. IST Austria, 2015, doi:10.15479/AT:IST-2015-323-v2-2.","ama":"Chatterjee K, Ibsen-Jensen R, Nowak M. *The Complexity of Evolutionary Games on Graphs*. IST Austria; 2015. doi:10.15479/AT:IST-2015-323-v2-2"},"department":[{"_id":"KrCh"}],"author":[{"orcid":"0000-0002-4561-241X","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","first_name":"Krishnendu"},{"first_name":"Rasmus","id":"3B699956-F248-11E8-B48F-1D18A9856A87","last_name":"Ibsen-Jensen","full_name":"Ibsen-Jensen, Rasmus","orcid":"0000-0003-4783-0389"},{"last_name":"Nowak","full_name":"Nowak, Martin","first_name":"Martin"}],"date_created":"2018-12-12T11:39:21Z","title":"The complexity of evolutionary games on graphs","pubrep_id":"338","type":"technical_report","_id":"5440","date_updated":"2021-01-12T08:02:20Z"},{"_id":"5441","type":"technical_report","date_updated":"2021-01-12T08:05:39Z","title":"Algorithms for algebraic path properties in concurrent systems of constant treewidth components","date_created":"2018-12-12T11:39:21Z","pubrep_id":"340","author":[{"first_name":"Krishnendu","orcid":"0000-0002-4561-241X","last_name":"Chatterjee","full_name":"Chatterjee, Krishnendu","id":"2E5DCA20-F248-11E8-B48F-1D18A9856A87"},{"orcid":"0000-0003-4783-0389","id":"3B699956-F248-11E8-B48F-1D18A9856A87","full_name":"Ibsen-Jensen, Rasmus","last_name":"Ibsen-Jensen","first_name":"Rasmus"},{"first_name":"Amir","full_name":"Goharshady, Amir","last_name":"Goharshady","id":"391365CE-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-1702-6584"},{"first_name":"Andreas","orcid":"0000-0002-8943-0722","id":"49704004-F248-11E8-B48F-1D18A9856A87","last_name":"Pavlogiannis","full_name":"Pavlogiannis, Andreas"}],"citation":{"ista":"Chatterjee K, Ibsen-Jensen R, Goharshady AK, Pavlogiannis A. 2015. Algorithms for algebraic path properties in concurrent systems of constant treewidth components, IST Austria, 24p.","ieee":"K. Chatterjee, R. Ibsen-Jensen, A. K. Goharshady, and A. Pavlogiannis, *Algorithms for algebraic path properties in concurrent systems of constant treewidth components*. IST Austria, 2015.","mla":"Chatterjee, Krishnendu, et al. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria, 2015, doi:10.15479/AT:IST-2015-340-v1-1.","ama":"Chatterjee K, Ibsen-Jensen R, Goharshady AK, Pavlogiannis A. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria; 2015. doi:10.15479/AT:IST-2015-340-v1-1","apa":"Chatterjee, K., Ibsen-Jensen, R., Goharshady, A. K., & Pavlogiannis, A. (2015). *Algorithms for algebraic path properties in concurrent systems of constant treewidth components*. IST Austria. https://doi.org/10.15479/AT:IST-2015-340-v1-1","chicago":"Chatterjee, Krishnendu, Rasmus Ibsen-Jensen, Amir Kafshdar Goharshady, and Andreas Pavlogiannis. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria, 2015. https://doi.org/10.15479/AT:IST-2015-340-v1-1.","short":"K. Chatterjee, R. Ibsen-Jensen, A.K. Goharshady, A. Pavlogiannis, Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components, IST Austria, 2015."},"department":[{"_id":"KrCh"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","page":"24","file_date_updated":"2020-07-14T12:46:56Z","oa_version":"Published Version","language":[{"iso":"eng"}],"day":"11","alternative_title":["IST Austria Technical Report"],"oa":1,"has_accepted_license":"1","related_material":{"record":[{"status":"public","relation":"later_version","id":"1437"},{"relation":"earlier_version","id":"5442","status":"public"},{"status":"public","id":"6009","relation":"later_version"}]},"status":"public","file":[{"file_id":"5531","checksum":"df383dc62c94d7b2ea639aba088a76c6","file_name":"IST-2015-340-v1+1_main.pdf","content_type":"application/pdf","file_size":861396,"creator":"system","relation":"main_file","date_created":"2018-12-12T11:54:09Z","access_level":"open_access","date_updated":"2020-07-14T12:46:56Z"}],"date_published":"2015-07-11T00:00:00Z","abstract":[{"text":"We study algorithmic questions for concurrent systems where the transitions are labeled from a complete, closed semiring, and path properties are algebraic with semiring operations. The algebraic path properties can model dataflow analysis problems, the shortest path problem, and many other natural problems that arise in program analysis. We consider that each component of the concurrent system is a graph with constant treewidth, a property satisfied by the controlflow graphs of most programs. We allow for multiple possible queries, which arise naturally in demand driven dataflow analysis. The study of multiple queries allows us to consider the tradeoff between the resource usage of the one-time preprocessing and for each individual query. The traditional approach constructs the product graph of all components and applies the best-known graph algorithm on the product. In this approach, even the answer to a single query requires the transitive closure (i.e., the results of all possible queries), which provides no room for tradeoff between preprocessing and query time. Our main contributions are algorithms that significantly improve the worst-case running time of the traditional approach, and provide various tradeoffs depending on the number of queries. For example, in a concurrent system of two components, the traditional approach requires hexic time in the worst case for answering one query as well as computing the transitive closure, whereas we show that with one-time preprocessing in almost cubic time, each subsequent query can be answered in at most linear time, and even the transitive closure can be computed in almost quartic time. Furthermore, we establish conditional optimality results showing that the worst-case running time of our algorithms cannot be improved without achieving major breakthroughs in graph algorithms (i.e., improving the worst-case bound for the shortest path problem in general graphs). Preliminary experimental results show that our algorithms perform favorably on several benchmarks.","lang":"eng"}],"month":"07","ddc":["000"],"doi":"10.15479/AT:IST-2015-340-v1-1","publication_identifier":{"issn":["2664-1690"]},"publisher":"IST Austria","year":"2015","publication_status":"published"},{"publication_status":"published","publisher":"IST Austria","publication_identifier":{"issn":["2664-1690"]},"year":"2015","ddc":["000"],"month":"07","date_published":"2015-07-14T00:00:00Z","abstract":[{"lang":"eng","text":"We study algorithmic questions for concurrent systems where the transitions are labeled from a complete, closed semiring, and path properties are algebraic with semiring operations. The algebraic path properties can model dataflow analysis problems, the shortest path problem, and many other natural properties that arise in program analysis.\r\nWe consider that each component of the concurrent system is a graph with constant treewidth, and it is known that the controlflow graphs of most programs have constant treewidth. We allow for multiple possible queries, which arise naturally in demand driven dataflow analysis problems (e.g., alias analysis). The study of multiple queries allows us to consider the tradeoff between the resource usage of the \\emph{one-time} preprocessing and for \\emph{each individual} query. The traditional approaches construct the product graph of all components and apply the best-known graph algorithm on the product. In the traditional approach, even the answer to a single query requires the transitive closure computation (i.e., the results of all possible queries), which provides no room for tradeoff between preprocessing and query time.\r\n\r\nOur main contributions are algorithms that significantly improve the worst-case running time of the traditional approach, and provide various tradeoffs depending on the number of queries. For example, in a concurrent system of two components, the traditional approach requires hexic time in the worst case for answering one query as well as computing the transitive closure, whereas we show that with one-time preprocessing in almost cubic time, \r\neach subsequent query can be answered in at most linear time, and even the transitive closure can be computed in almost quartic time. Furthermore, we establish conditional optimality results that show that the worst-case running times of our algorithms cannot be improved without achieving major breakthroughs in graph algorithms (such as improving \r\nthe worst-case bounds for the shortest path problem in general graphs whose current best-known bound has not been improved in five decades). Finally, we provide a prototype implementation of our algorithms which significantly outperforms the existing algorithmic methods on several benchmarks."}],"scopus_import":1,"related_material":{"record":[{"status":"public","relation":"later_version","id":"5441"},{"id":"1437","relation":"later_version","status":"public"},{"id":"6009","relation":"later_version","status":"public"}]},"status":"public","file":[{"file_name":"IST-2015-343-v2+1_main.pdf","content_type":"application/pdf","creator":"system","file_size":658747,"file_id":"5498","checksum":"98fd936102f3e057fc321ef6d316001d","access_level":"open_access","date_updated":"2020-07-14T12:46:57Z","relation":"main_file","date_created":"2018-12-12T11:53:37Z"},{"date_created":"2019-04-16T12:36:08Z","relation":"main_file","date_updated":"2020-07-14T12:46:57Z","access_level":"closed","checksum":"b31d09b1241b59c75e1f42dadf09d258","file_id":"6316","file_size":139,"creator":"dernst","file_name":"IST-2015-343-v2+2_anonymous.txt","content_type":"text/plain"}],"day":"14","alternative_title":["IST Austria Technical Report"],"has_accepted_license":"1","oa":1,"oa_version":"Published Version","language":[{"iso":"eng"}],"page":"22","file_date_updated":"2020-07-14T12:46:57Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"first_name":"1","last_name":"Anonymous","full_name":"Anonymous, 1"},{"first_name":"2","last_name":"Anonymous","full_name":"Anonymous, 2"},{"full_name":"Anonymous, 3","last_name":"Anonymous","first_name":"3"},{"last_name":"Anonymous","full_name":"Anonymous, 4","first_name":"4"}],"citation":{"short":"1 Anonymous, 2 Anonymous, 3 Anonymous, 4 Anonymous, Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components, IST Austria, 2015.","chicago":"Anonymous, 1, 2 Anonymous, 3 Anonymous, and 4 Anonymous. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria, 2015.","ieee":"1 Anonymous, 2 Anonymous, 3 Anonymous, and 4 Anonymous, *Algorithms for algebraic path properties in concurrent systems of constant treewidth components*. IST Austria, 2015.","ista":"Anonymous 1, Anonymous 2, Anonymous 3, Anonymous 4. 2015. Algorithms for algebraic path properties in concurrent systems of constant treewidth components, IST Austria, 22p.","apa":"Anonymous, 1, Anonymous, 2, Anonymous, 3, & Anonymous, 4. (2015). *Algorithms for algebraic path properties in concurrent systems of constant treewidth components*. IST Austria.","ama":"Anonymous 1, Anonymous 2, Anonymous 3, Anonymous 4. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria; 2015.","mla":"Anonymous, 1, et al. *Algorithms for Algebraic Path Properties in Concurrent Systems of Constant Treewidth Components*. IST Austria, 2015."},"title":"Algorithms for algebraic path properties in concurrent systems of constant treewidth components","date_created":"2018-12-12T11:39:21Z","pubrep_id":"344","_id":"5442","date_updated":"2021-01-12T08:05:39Z","type":"technical_report"}]