@article{11758, author = {Aceto, Luca and Henzinger, Monika H and Sgall, Jiří}, issn = {0890-5401}, journal = {Information and Computation}, number = {1}, pages = {1}, publisher = {Elsevier}, title = {{38th International Colloquium on Automata, Languages and Programming}}, doi = {10.1016/j.ic.2012.11.002}, volume = {222}, year = {2013}, } @article{11759, abstract = {Matching markets play a prominent role in economic theory. A prime example of such a market is the sponsored search market. Here, as in other markets of that kind, market equilibria correspond to feasible, envy free, and bidder optimal outcomes. For settings without budgets such an outcome always exists and can be computed in polynomial-time by the so-called Hungarian Method. Moreover, every mechanism that computes such an outcome is incentive compatible. We show that the Hungarian Method can be modified so that it finds a feasible, envy free, and bidder optimal outcome for settings with budgets. We also show that in settings with budgets no mechanism that computes such an outcome can be incentive compatible for all inputs. For inputs in general position, however, the presented mechanism—as any other mechanism that computes such an outcome for settings with budgets—is incentive compatible.}, author = {Dütting, Paul and Henzinger, Monika H and Weber, Ingmar}, issn = {0020-0190}, journal = {Information Processing Letters}, number = {3}, pages = {67--73}, publisher = {Elsevier}, title = {{Sponsored search, market equilibria, and the Hungarian Method}}, doi = {10.1016/j.ipl.2012.11.006}, volume = {113}, year = {2013}, } @inproceedings{11791, abstract = {The focus of classic mechanism design has been on truthful direct-revelation mechanisms. In the context of combinatorial auctions the truthful direct-revelation mechanism that maximizes social welfare is the VCG mechanism. For many valuation spaces computing the allocation and payments of the VCG mechanism, however, is a computationally hard problem. We thus study the performance of the VCG mechanism when bidders are forced to choose bids from a subspace of the valuation space for which the VCG outcome can be computed efficiently. We prove improved upper bounds on the welfare loss for restrictions to additive bids and upper and lower bounds for restrictions to non-additive bids. These bounds show that the welfare loss increases in expressiveness. All our bounds apply to equilibrium concepts that can be computed in polynomial time as well as to learning outcomes.}, author = {Dütting, Paul and Henzinger, Monika H and Starnberger, Martin}, booktitle = {9th International Conference on Web and Internet Economics}, isbn = {9783642450457}, issn = {1611-3349}, location = {Cambridge, MA, USA}, pages = {146–159}, publisher = {Springer Nature}, title = {{Valuation compressions in VCG-based combinatorial auctions}}, doi = {10.1007/978-3-642-45046-4_13}, volume = {8289}, year = {2013}, } @inproceedings{11792, abstract = {We study the problem of maximizing a monotone submodular function with viability constraints. This problem originates from computational biology, where we are given a phylogenetic tree over a set of species and a directed graph, the so-called food web, encoding viability constraints between these species. These food webs usually have constant depth. The goal is to select a subset of k species that satisfies the viability constraints and has maximal phylogenetic diversity. As this problem is known to be NP-hard, we investigate approximation algorithm. We present the first constant factor approximation algorithm if the depth is constant. Its approximation ratio is (1−1𝑒√). This algorithm not only applies to phylogenetic trees with viability constraints but for arbitrary monotone submodular set functions with viability constraints. Second, we show that there is no (1 − 1/e + ε)-approximation algorithm for our problem setting (even for additive functions) and that there is no approximation algorithm for a slight extension of this setting.}, author = {Dvořák, Wolfgang and Henzinger, Monika H and Williamson, David P.}, booktitle = {21st Annual European Symposium on Algorithms}, isbn = {9783642404498}, issn = {1611-3349}, location = {Sophia Antipolis, France}, pages = {409 -- 420}, publisher = {Springer Nature}, title = {{Maximizing a submodular function with viability constraints}}, doi = {10.1007/978-3-642-40450-4_35}, volume = {8125}, year = {2013}, } @inproceedings{11793, abstract = {We study the problem of maintaining a breadth-first spanning tree (BFS tree) in partially dynamic distributed networks modeling a sequence of either failures or additions of communication links (but not both). We show (1 + ε)-approximation algorithms whose amortized time (over some number of link changes) is sublinear in D, the maximum diameter of the network. This breaks the Θ(D) time bound of recomputing “from scratch”. Our technique also leads to a (1 + ε)-approximate incremental algorithm for single-source shortest paths (SSSP) in the sequential (usual RAM) model. Prior to our work, the state of the art was the classic exact algorithm of [9] that is optimal under some assumptions [27]. Our result is the first to show that, in the incremental setting, this bound can be beaten in certain cases if a small approximation is allowed.}, author = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon}, booktitle = {40th International Colloquium on Automata, Languages, and Programming}, isbn = {9783642392115}, issn = {1611-3349}, location = {Riga, Latvia}, pages = {607–619}, publisher = {Springer Nature}, title = {{Sublinear-time maintenance of breadth-first spanning tree in partially dynamic networks}}, doi = {10.1007/978-3-642-39212-2_53}, volume = {7966}, year = {2013}, } @inproceedings{11856, abstract = {We study dynamic (1 + ϵ)-approximation algorithms for the all-pairs shortest paths problem in unweighted undirected n-node m-edge graphs under edge deletions. The fastest algorithm for this problem is a randomized algorithm with a total update time of Ȏ(mn) and constant query time by Roditty and Zwick (FOCS 2004). The fastest deterministic algorithm is from a 1981 paper by Even and Shiloach (JACM 1981); it has a total update time of O(mn 2 ) and constant query time. We improve these results as follows: (1) We present an algorithm with a total update time of Ȏ(n 5/2 ) and constant query time that has an additive error of two in addition to the 1 + ϵ multiplicative error. This beats the previous Ȏ(mn) time when m = Ω(n 3/2 ). Note that the additive error is unavoidable since, even in the static case, an O(n 3-δ )-time (a so-called truly sub cubic) combinatorial algorithm with 1 + ϵ multiplicative error cannot have an additive error less than 2 - ϵ, unless we make a major breakthrough for Boolean matrix multiplication (Dor, Halperin and Zwick FOCS 1996) and many other long-standing problems (Vassilevska Williams and Williams FOCS 2010). The algorithm can also be turned into a (2 + ϵ)-approximation algorithm (without an additive error) with the same time guarantees, improving the recent (3 + ϵ)-approximation algorithm with Ȏ(n 5/2+O(1√(log n)) ) running time of Bernstein and Roditty (SODA 2011) in terms of both approximation and time guarantees. (2) We present a deterministic algorithm with a total update time of Ȏ(mn) and a query time of O(log log n). The algorithm has a multiplicative error of 1 + ϵ and gives the first improved deterministic algorithm since 1981. It also answers an open question raised by Bernstein in his STOC 2013 paper. In order to achieve our results, we introduce two new techniques: (1) A lazy Even-Shiloach tree algorithm which maintains a bounded-distance shortest-paths tree on a certain type of emulator called locally persevering emulator. (2) A derandomization technique based on moving Even-Shiloach trees as a way to derandomize the standard random set argument. These techniques might be of independent interest.}, author = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon}, booktitle = {54th Annual Symposium on Foundations of Computer Science}, issn = {0272-5428}, location = {Berkeley, CA, United States}, pages = {538--547}, publisher = {Institute of Electrical and Electronics Engineers}, title = {{Dynamic approximate all-pairs shortest paths: Breaking the O(mn) barrier and derandomization}}, doi = {10.1109/focs.2013.64}, year = {2013}, } @article{11902, abstract = {We study the problem of matching bidders to items where each bidder i has general, strictly monotonic utility functions ui,j(pj) expressing his utility of being matched to item j at price pj. For this setting we prove that a bidder optimal outcome always exists, even when the utility functions are non-linear and non-continuous. We give sufficient conditions under which every mechanism that finds a bidder optimal outcome is incentive compatible. We also give a mechanism that finds a bidder optimal outcome if the conditions for incentive compatibility are satisfied. The running time of this mechanism is exponential in the number of items, but polynomial in the number of bidders.}, author = {Dütting, Paul and Henzinger, Monika H and Weber, Ingmar}, issn = {0304-3975}, journal = {Theoretical Computer Science}, number = {3}, pages = {22--32}, publisher = {Elsevier}, title = {{Bidder optimal assignments for general utilities}}, doi = {10.1016/j.tcs.2013.01.030}, volume = {478}, year = {2013}, } @article{11959, abstract = {No catalyst required! A highly efficient, catalyst-free process to generate diimide in situ from hydrazine monohydrate and molecular oxygen for the selective reduction of alkenes has been developed. The use of a gas–liquid segmented flow system allowed safe operating conditions and dramatically enhanced this atom-economical reaction, resulting in short processing times.}, author = {Pieber, Bartholomäus and Martinez, Sabrina Teixeira and Cantillo, David and Kappe, C. Oliver}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, number = {39}, pages = {10241--10244}, publisher = {Wiley}, title = {{In situ generation of diimide from hydrazine and oxygen: Continuous-flow transfer hydrogenation of olefins}}, doi = {10.1002/anie.201303528}, volume = {52}, year = {2013}, } @article{11960, abstract = {It's not magic! The effects observed in microwave-irradiated chemical transformations can in most cases be rationalized by purely bulk thermal phenomena associated with rapid heating to elevated temperatures. As discussed in this Essay, the existence of so-called nonthermal or specific microwave effects is highly doubtful.}, author = {Kappe, C. Oliver and Pieber, Bartholomäus and Dallinger, Doris}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, number = {4}, pages = {1088--1094}, publisher = {Wiley}, title = {{Microwave effects in organic synthesis: Myth or reality?}}, doi = {10.1002/anie.201204103}, volume = {52}, year = {2013}, } @article{11973, abstract = {The use of high-temperature/pressure gas–liquid continuous flow conditions dramatically enhances the iron-catalyzed aerobic oxidation of 2-benzylpyridines to their corresponding ketones. Pressurized air serves as a readily available oxygen source and propylene carbonate as a green solvent in this radically intensified preparation of synthetically valuable 2-aroylpyridines.}, author = {Pieber, Bartholomäus and Kappe, C. Oliver}, issn = {1463-9270}, journal = {Green Chemistry}, number = {2}, pages = {320--324}, publisher = {Royal Society of Chemistry}, title = {{Direct aerobic oxidation of 2-benzylpyridines in a gas-liquid continuous-flow regime using propylene carbonate as a solvent}}, doi = {10.1039/c2gc36896j}, volume = {15}, year = {2013}, } @article{2204, abstract = {We introduce a new platform for quantum simulation of many-body systems based on nonspherical atoms or molecules with zero dipole moments but possessing a significant value of electric quadrupole moments. We consider a quadrupolar Fermi gas trapped in a 2D square optical lattice, and show that the peculiar symmetry and broad tunability of the quadrupole-quadrupole interaction results in a rich phase diagram encompassing unconventional BCS and charge density wave phases, and opens up a perspective to create a topological superfluid. Quadrupolar species, such as metastable alkaline-earth atoms and homonuclear molecules, are stable against chemical reactions and collapse and are readily available in experiment at high densities.}, author = {Bhongale, Satyan and Mathey, Ludwig and Zhao, Erhai and Yelin, Susanne and Lemeshko, Mikhail}, journal = {Physical Review Letters}, number = {15}, publisher = {American Physical Society}, title = {{Quantum phases of quadrupolar fermi gases in optical lattices}}, doi = {10.1103/PhysRevLett.110.155301}, volume = {110}, year = {2013}, } @misc{2205, abstract = {The goal of the present article is to review the major developments that have led to the current understanding of molecule-field interactions and experimental methods for manipulating molecules with electromagnetic fields. Molecule-field interactions are at the core of several, seemingly distinct areas of molecular physics. This is reflected in the organisation of this article, which includes sections on field control of molecular beams, external field traps for cold molecules, control of molecular orientation and molecular alignment, manipulation of molecules by non-conservative forces, ultracold molecules and ultracold chemistry, controlled many-body phenomena, entanglement of molecules and dipole arrays, and stability of molecular systems in high-frequency super-intense laser fields. The article contains 852 references.}, author = {Mikhail Lemeshko and Krems, Roman V and Doyle, John M and Kais, Sabre}, booktitle = {Molecular Physics}, number = {12-13}, pages = {1648 -- 1682}, publisher = {Taylor & Francis}, title = {{Manipulation of molecules with electromagnetic fields}}, doi = {10.1080/00268976.2013.813595}, volume = {111}, year = {2013}, } @article{2206, abstract = {Magnetic impurities embedded in inert solids can exhibit long coherence times and interact with one another via their intrinsic anisotropic dipolar interaction. We argue that, as a consequence of these properties, disordered ensembles of magnetic impurities provide an effective platform for realizing a controllable, tunable version of the dipolar quantum spin glass seen in LiHoxY1-xF4. Specifically, we propose and analyze a system composed of dysprosium atoms embedded in solid helium. We describe the phase diagram of the system and discuss the realizability and detectability of the quantum spin glass and antiglass phases.}, author = {Mikhail Lemeshko and Yao, Norman Y and Gorshkov, Alexey V and Weimer, Hendrik and Bennett, Steven D and Momose, Takamasa and Gopalakrishnan, Sarang}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {1}, publisher = {American Physical Society}, title = {{Controllable quantum spin glasses with magnetic impurities embedded in quantum solids}}, doi = {10.1103/PhysRevB.88.014426}, volume = {88}, year = {2013}, } @article{2207, abstract = {The formation of molecules and supramolecular structures results from bonding by conservative forces acting among electrons and nuclei and giving rise to equilibrium configurations defined by minima of the interaction potential. Here we show that bonding can also occur by the non-conservative forces responsible for interaction-induced coherent population trapping. The bound state arises in a dissipative process and manifests itself as a stationary state at a preordained interatomic distance. Remarkably, such a dissipative bonding is present even when the interactions among the atoms are purely repulsive. The dissipative bound states can be created and studied spectroscopically in present-day experiments with ultracold atoms or molecules and can potentially serve for cooling strongly interacting quantum gases.}, author = {Mikhail Lemeshko and Weimer, Hendrik}, journal = {Nature Communications}, publisher = {Nature Publishing Group}, title = {{Dissipative binding of atoms by non-conservative forces}}, doi = {10.1038/ncomms3230}, volume = {4}, year = {2013}, } @inproceedings{2209, abstract = {A straight skeleton is a well-known geometric structure, and several algorithms exist to construct the straight skeleton for a given polygon or planar straight-line graph. In this paper, we ask the reverse question: Given the straight skeleton (in form of a planar straight-line graph, with some rays to infinity), can we reconstruct a planar straight-line graph for which this was the straight skeleton? We show how to reduce this problem to the problem of finding a line that intersects a set of convex polygons. We can find these convex polygons and all such lines in $O(nlog n)$ time in the Real RAM computer model, where $n$ denotes the number of edges of the input graph. We also explain how our approach can be used for recognizing Voronoi diagrams of points, thereby completing a partial solution provided by Ash and Bolker in 1985. }, author = {Biedl, Therese and Held, Martin and Huber, Stefan}, location = {St. Petersburg, Russia}, pages = {37 -- 46}, publisher = {IEEE}, title = {{Recognizing straight skeletons and Voronoi diagrams and reconstructing their input}}, doi = {10.1109/ISVD.2013.11}, year = {2013}, } @inproceedings{2210, abstract = {A straight skeleton is a well-known geometric structure, and several algorithms exist to construct the straight skeleton for a given polygon. In this paper, we ask the reverse question: Given the straight skeleton (in form of a tree with a drawing in the plane, but with the exact position of the leaves unspecified), can we reconstruct the polygon? We show that in most cases there exists at most one polygon; in the remaining case there is an infinite number of polygons determined by one angle that can range in an interval. We can find this (set of) polygon(s) in linear time in the Real RAM computer model.}, author = {Biedl, Therese and Held, Martin and Huber, Stefan}, booktitle = {29th European Workshop on Computational Geometry}, location = {Braunschweig, Germany}, pages = {95 -- 98}, publisher = {TU Braunschweig}, title = {{Reconstructing polygons from embedded straight skeletons}}, year = {2013}, } @inproceedings{2237, abstract = {We describe new extensions of the Vampire theorem prover for computing tree interpolants. These extensions generalize Craig interpolation in Vampire, and can also be used to derive sequence interpolants. We evaluated our implementation on a large number of examples over the theory of linear integer arithmetic and integer-indexed arrays, with and without quantifiers. When compared to other methods, our experiments show that some examples could only be solved by our implementation.}, author = {Blanc, Régis and Gupta, Ashutosh and Kovács, Laura and Kragl, Bernhard}, location = {Stellenbosch, South Africa}, pages = {173 -- 181}, publisher = {Springer}, title = {{Tree interpolation in Vampire}}, doi = {10.1007/978-3-642-45221-5_13}, volume = {8312}, year = {2013}, } @inproceedings{2238, abstract = {We study the problem of achieving a given value in Markov decision processes (MDPs) with several independent discounted reward objectives. We consider a generalised version of discounted reward objectives, in which the amount of discounting depends on the states visited and on the objective. This definition extends the usual definition of discounted reward, and allows to capture the systems in which the value of different commodities diminish at different and variable rates. We establish results for two prominent subclasses of the problem, namely state-discount models where the discount factors are only dependent on the state of the MDP (and independent of the objective), and reward-discount models where they are only dependent on the objective (but not on the state of the MDP). For the state-discount models we use a straightforward reduction to expected total reward and show that the problem whether a value is achievable can be solved in polynomial time. For the reward-discount model we show that memory and randomisation of the strategies are required, but nevertheless that the problem is decidable and it is sufficient to consider strategies which after a certain number of steps behave in a memoryless way. For the general case, we show that when restricted to graphs (i.e. MDPs with no randomisation), pure strategies and discount factors of the form 1/n where n is an integer, the problem is in PSPACE and finite memory suffices for achieving a given value. We also show that when the discount factors are not of the form 1/n, the memory required by a strategy can be infinite. }, author = {Chatterjee, Krishnendu and Forejt, Vojtěch and Wojtczak, Dominik}, location = {Stellenbosch, South Africa}, pages = {228 -- 242}, publisher = {Springer}, title = {{Multi-objective discounted reward verification in graphs and MDPs}}, doi = {10.1007/978-3-642-45221-5_17}, volume = {8312}, year = {2013}, } @inproceedings{2243, abstract = {We show that modal logic over universally first-order definable classes of transitive frames is decidable. More precisely, let K be an arbitrary class of transitive Kripke frames definable by a universal first-order sentence. We show that the global and finite global satisfiability problems of modal logic over K are decidable in NP, regardless of choice of K. We also show that the local satisfiability and the finite local satisfiability problems of modal logic over K are decidable in NEXPTIME.}, author = {Michaliszyn, Jakub and Otop, Jan}, location = {Torino, Italy}, pages = {563 -- 577}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Elementary modal logics over transitive structures}}, doi = {10.4230/LIPIcs.CSL.2013.563}, volume = {23}, year = {2013}, } @inproceedings{2244, abstract = {We consider two systems (α1,...,αm) and (β1,...,βn) of curves drawn on a compact two-dimensional surface ℳ with boundary. Each αi and each βj is either an arc meeting the boundary of ℳ at its two endpoints, or a closed curve. The αi are pairwise disjoint except for possibly sharing endpoints, and similarly for the βj. We want to "untangle" the βj from the αi by a self-homeomorphism of ℳ; more precisely, we seek an homeomorphism φ: ℳ → ℳ fixing the boundary of ℳ pointwise such that the total number of crossings of the αi with the φ(βj) is as small as possible. This problem is motivated by an application in the algorithmic theory of embeddings and 3-manifolds. We prove that if ℳ is planar, i.e., a sphere with h ≥ 0 boundary components ("holes"), then O(mn) crossings can be achieved (independently of h), which is asymptotically tight, as an easy lower bound shows. In general, for an arbitrary (orientable or nonorientable) surface ℳ with h holes and of (orientable or nonorientable) genus g ≥ 0, we obtain an O((m + n)4) upper bound, again independent of h and g. }, author = {Matoušek, Jiří and Sedgwick, Eric and Tancer, Martin and Wagner, Uli}, location = {Bordeaux, France}, pages = {472 -- 483}, publisher = {Springer}, title = {{Untangling two systems of noncrossing curves}}, doi = {10.1007/978-3-319-03841-4_41}, volume = {8242}, year = {2013}, }