@article{695,
  abstract     = {It has been known since Stefan Vogel's observations in 1969 that solitary female oil bees collect fatty floral oils from specialized oil-secreting plants with the aid of hairy patches on either their legs or abdomen, a reward used as food for their larvae and/or to line their brood cells. Similar adaptations are also known from male oil bees, although the purpose of their oil-collecting behavior has not yet been clarified. Here, we describe a novel pollination system involving male Paratetrapedia oil bees and the tropical herb Anthurium acutifolium. We present ultrastructural morphological details of bee and plant structures involved in this interaction and the composition of floral scents likely mediating pollinator attraction. Inflorescences of A. acutifolium were visited almost exclusively by male P. chocoensis oil bees. The bees mopped with a hairy patch of their abdominal sterna 3 across the inflorescence surface. During this activity on both staminate and pistillate stage inflorescences, bees’ abdomens and legs became loaded with pollen and contacted receptive stigmas. In contrast to what has been observed in other angiosperms visited for the collection of fatty floral oils, the inflorescences/flowers of A. acutifolium do not have structures specialized in oil secretion, i.e., elaiophores. These inflorescences, nonetheless, were strongly scented during the time interval they were visited by the bees. Gas chromatography/mass spectrometry (GC/MS) analyses of dynamic headspace floral samples revealed that inflorescences of both anthetic phases emitted scent bouquets consisting mainly of aliphatic esters, indole and uncommmon terpenoids (megastigmanes). Interestingly enough, our data suggest that the unusual floral scent of A. acutifolium is a perfume reward collected by male P. chocoensis oil bees. This pollination system thus bears a remarkable resemblence with the interactions between perfume-collecting male euglossine bees and their preferred flowers, discovered by Stefan Vogel half a century ago.},
  author       = {Etl, Florian and Franschitz, Anna and Aguiar, Antonio and Schönenberger, Jürg and Dötterl, Stefan},
  issn         = {03672530},
  journal      = {Flora: Morphology, Distribution, Functional Ecology of Plants},
  pages        = {7 -- 15},
  publisher    = {Elsevier},
  title        = {{A perfume collecting male oil bee? Evidences of a novel pollination system involving Anthurium acutifolium Araceae and Paratetrapedia chocoensis Apidae Tapinotaspidini}},
  doi          = {10.1016/j.flora.2017.02.020},
  volume       = {232},
  year         = {2017},
}

@inproceedings{697,
  abstract     = {De, Trevisan and Tulsiani [CRYPTO 2010] show that every distribution over n-bit strings which has constant statistical distance to uniform (e.g., the output of a pseudorandom generator mapping n-1 to n bit strings), can be distinguished from the uniform distribution with advantage epsilon by a circuit of size O( 2^n epsilon^2). We generalize this result, showing that a distribution which has less than k bits of min-entropy, can be distinguished from any distribution with k bits of delta-smooth min-entropy with advantage epsilon by a circuit of size O(2^k epsilon^2/delta^2). As a special case, this implies that any distribution with support at most 2^k (e.g., the output of a pseudoentropy generator mapping k to n bit strings) can be distinguished from any given distribution with min-entropy k+1 with advantage epsilon by a circuit of size O(2^k epsilon^2). Our result thus shows that pseudoentropy distributions face basically the same non-uniform attacks as pseudorandom distributions. },
  author       = {Pietrzak, Krzysztof Z and Skórski, Maciej},
  issn         = {1868-8969},
  location     = {Warsaw, Poland},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{Non uniform attacks against pseudoentropy}},
  doi          = {10.4230/LIPIcs.ICALP.2017.39},
  volume       = {80},
  year         = {2017},
}

@article{698,
  abstract     = {Extracellular matrix signals from the microenvironment regulate gene expression patterns and cell behavior. Using a combination of experiments and geometric models, we demonstrate correlations between cell geometry, three-dimensional (3D) organization of chromosome territories, and gene expression. Fluorescence in situ hybridization experiments showed that micropatterned fibroblasts cultured on anisotropic versus isotropic substrates resulted in repositioning of specific chromosomes, which contained genes that were differentially regulated by cell geometries. Experiments combined with ellipsoid packing models revealed that the mechanosensitivity of chromosomes was correlated with their orientation in the nucleus. Transcription inhibition experiments suggested that the intermingling degree was more sensitive to global changes in transcription than to chromosome radial positioning and its orientations. These results suggested that cell geometry modulated 3D chromosome arrangement, and their neighborhoods correlated with gene expression patterns in a predictable manner. This is central to understanding geometric control of genetic programs involved in cellular homeostasis and the associated diseases. },
  author       = {Wang, Yejun and Nagarajan, Mallika and Uhler, Caroline and Shivashankar, Gv},
  issn         = {1059-1524},
  journal      = {Molecular Biology of the Cell},
  number       = {14},
  pages        = {1997 -- 2009},
  publisher    = {American Society for Cell Biology},
  title        = {{Orientation and repositioning of chromosomes correlate with cell geometry dependent gene expression}},
  doi          = {10.1091/mbc.E16-12-0825},
  volume       = {28},
  year         = {2017},
}

@article{699,
  abstract     = {In antagonistic symbioses, such as host–parasite interactions, one population’s success is the other’s loss. In mutualistic symbioses, such as division of labor, both parties can gain, but they might have different preferences over the possible mutualistic arrangements. The rates of evolution of the two populations in a symbiosis are important determinants of which population will be more successful: Faster evolution is thought to be favored in antagonistic symbioses (the “Red Queen effect”), but disfavored in certain mutualistic symbioses (the “Red King effect”). However, it remains unclear which biological parameters drive these effects. Here, we analyze the effects of the various determinants of evolutionary rate: generation time, mutation rate, population size, and the intensity of natural selection. Our main results hold for the case where mutation is infrequent. Slower evolution causes a long-term advantage in an important class of mutualistic interactions. Surprisingly, less intense selection is the strongest driver of this Red King effect, whereas relative mutation rates and generation times have little effect. In antagonistic interactions, faster evolution by any means is beneficial. Our results provide insight into the demographic evolution of symbionts. },
  author       = {Veller, Carl and Hayward, Laura and Nowak, Martin and Hilbe, Christian},
  issn         = {0027-8424},
  journal      = {PNAS},
  number       = {27},
  pages        = {E5396 -- E5405},
  publisher    = {National Academy of Sciences},
  title        = {{The red queen and king in finite populations}},
  doi          = {10.1073/pnas.1702020114},
  volume       = {114},
  year         = {2017},
}

@article{700,
  abstract     = {Microtubules provide the mechanical force required for chromosome separation during mitosis. However, little is known about the dynamic (high-frequency) mechanical properties of microtubules. Here, we theoretically propose to control the vibrations of a doubly clamped microtubule by tip electrodes and to detect its motion via the optomechanical coupling between the vibrational modes of the microtubule and an optical cavity. In the presence of a red-detuned strong pump laser, this coupling leads to optomechanical-induced transparency of an optical probe field, which can be detected with state-of-the art technology. The center frequency and line width of the transparency peak give the resonance frequency and damping rate of the microtubule, respectively, while the height of the peak reveals information about the microtubule-cavity field coupling. Our method opens the new possibilities to gain information about the physical properties of microtubules, which will enhance our capability to design physical cancer treatment protocols as alternatives to chemotherapeutic drugs.},
  author       = {Barzanjeh, Shabir and Salari, Vahid and Tuszynski, Jack and Cifra, Michal and Simon, Christoph},
  issn         = {2470-0045},
  journal      = { Physical Review E Statistical Nonlinear and Soft Matter Physics },
  number       = {1},
  publisher    = {American Institute of Physics},
  title        = {{Optomechanical proposal for monitoring microtubule mechanical vibrations}},
  doi          = {10.1103/PhysRevE.96.012404},
  volume       = {96},
  year         = {2017},
}

@article{701,
  abstract     = {A d-dimensional simplex S is called a k-reptile (or a k-reptile simplex) if it can be tiled by k simplices with disjoint interiors that are all mutually congruent and similar to S. For d = 2, triangular k-reptiles exist for all k of the form a^2, 3a^2 or a^2+b^2 and they have been completely characterized by Snover, Waiveris, and Williams. On the other hand, the only k-reptile simplices that are known for d ≥ 3, have k = m^d, where m is a positive integer. We substantially simplify the proof by Matoušek and the second author that for d = 3, k-reptile tetrahedra can exist only for k = m^3. We then prove a weaker analogue of this result for d = 4 by showing that four-dimensional k-reptile simplices can exist only for k = m^2.},
  author       = {Kynčl, Jan and Patakova, Zuzana},
  issn         = {1077-8926},
  journal      = {The Electronic Journal of Combinatorics},
  number       = {3},
  pages        = {1--44},
  publisher    = {International Press},
  title        = {{On the nonexistence of k reptile simplices in ℝ^3 and ℝ^4}},
  volume       = {24},
  year         = {2017},
}

@article{702,
  abstract     = {Leading autism-associated mutation in mouse partially mimics human disorder.

},
  author       = {Novarino, Gaia},
  issn         = {1946-6234},
  journal      = {Science Translational Medicine},
  number       = {399},
  pages        = {eaao0972},
  publisher    = {American Association for the Advancement of Science},
  title        = {{The riddle of CHD8 haploinsufficiency in autism spectrum disorder}},
  doi          = {10.1126/scitranslmed.aao0972},
  volume       = {9},
  year         = {2017},
}

@article{706,
  abstract     = {A hippocampal mossy fiber synapse has a complex structure and is implicated in learning and memory. In this synapse, the mossy fiber boutons attach to the dendritic shaft by puncta adherentia junctions and wrap around a multiply-branched spine, forming synaptic junctions. We have recently shown using transmission electron microscopy, immunoelectron microscopy and serial block face-scanning electron microscopy that atypical puncta adherentia junctions are formed in the afadin-deficient mossy fiber synapse and that the complexity of postsynaptic spines and mossy fiber boutons, the number of spine heads, the area of postsynaptic densities and the density of synaptic vesicles docked to active zones are decreased in the afadin-deficient synapse. We investigated here the roles of afadin in the functional differentiations of the mossy fiber synapse using the afadin-deficient mice. The electrophysiological studies showed that both the release probability of glutamate and the postsynaptic responsiveness to glutamate were markedly reduced, but not completely lost, in the afadin-deficient mossy fiber synapse, whereas neither long-term potentiation nor long-term depression was affected. These results indicate that afadin plays roles in the functional differentiations of the presynapse and the postsynapse of the hippocampal mossy fiber synapse.},
  author       = {Geng, Xiaoqi and Maruo, Tomohiko and Mandai, Kenji and Supriyanto, Irwan and Miyata, Muneaki and Sakakibara, Shotaro and Mizoguchi, Akira and Takai, Yoshimi and Mori, Masahiro},
  issn         = {1356-9597},
  journal      = {Genes to Cells},
  number       = {8},
  pages        = {715 -- 722},
  publisher    = {Wiley-Blackwell},
  title        = {{Roles of afadin in functional differentiations of hippocampal mossy fiber synapse}},
  doi          = {10.1111/gtc.12508},
  volume       = {22},
  year         = {2017},
}

@article{7064,
  abstract     = {The complex antiferromagnetic orders observed in the honeycomb iridates are a double-edged sword in the search for a quantum spin-liquid: both attesting that the magnetic interactions provide many of the necessary ingredients, while simultaneously impeding access. Focus has naturally been drawn to the unusual magnetic orders that hint at the underlying spin correlations. However, the study of any particular broken symmetry state generally provides little clue about the possibility of other nearby ground states. Here we use magnetic fields approaching 100 Tesla to reveal the extent of the spin correlations in γ-lithium iridate. We find that a small component of field along the magnetic easy-axis melts long-range order, revealing a bistable, strongly correlated spin state. Far from the usual destruction of antiferromagnetism via spin polarization, the high-field state possesses only a small fraction of the total iridium moment, without evidence for long-range order up to the highest attainable magnetic fields.},
  author       = {Modic, Kimberly A and Ramshaw, B. J. and Betts, J. B. and Breznay, Nicholas P. and Analytis, James G. and McDonald, Ross D. and Shekhter, Arkady},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  number       = {1},
  publisher    = {Springer Nature},
  title        = {{Robust spin correlations at high magnetic fields in the harmonic honeycomb iridates}},
  doi          = {10.1038/s41467-017-00264-6},
  volume       = {8},
  year         = {2017},
}

@article{7065,
  abstract     = {Magneto-quantum oscillation experiments in high-temperature superconductors show a strong thermally induced suppression of the oscillation amplitude approaching the critical dopings [B. J. Ramshaw et al., Science 348, 317 (2014); H. Shishido et al., Phys. Rev. Lett. 104, 057008 (2010); P. Walmsley et al., Phys. Rev. Lett. 110, 257002 (2013)]—in support of a quantum-critical origin of their phase diagrams. We suggest that, in addition to a thermodynamic mass enhancement, these experiments may directly indicate the increasing role of quantum fluctuations that suppress the quantum oscillation amplitude through inelastic scattering. We show that the traditional theoretical approaches beyond Lifshitz-Kosevich to calculate the oscillation amplitude in correlated metals result in a contradiction with the third law of thermodynamics and suggest a way to rectify this problem.},
  author       = {Shekhter, Arkady and Modic, Kimberly A and McDonald, R. D. and Ramshaw, B. J.},
  issn         = {2469-9969},
  journal      = {Physical Review B},
  number       = {12},
  publisher    = {APS},
  title        = {{Thermodynamic constraints on the amplitude of quantum oscillations}},
  doi          = {10.1103/physrevb.95.121106},
  volume       = {95},
  year         = {2017},
}

@article{7066,
  abstract     = {The excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematic study of the BCS-BEC-like crossover by means of conventional condensed matter probes.},
  author       = {Zhu, Z. and McDonald, R. D. and Shekhter, A. and Ramshaw, B. J. and Modic, Kimberly A and Balakirev, F. F. and Harrison, N.},
  issn         = {2045-2322},
  journal      = {Scientific Reports},
  publisher    = {Springer Nature},
  title        = {{Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite}},
  doi          = {10.1038/s41598-017-01693-5},
  volume       = {7},
  year         = {2017},
}

@article{7067,
  abstract     = {Broken fourfold rotational (C4) symmetry is observed in the experimental properties of several classes of unconventional superconductors. It has been proposed that this symmetry breaking is important for superconducting pairing in these materials, but in the high-Tc cuprates this broken symmetry has never been observed on the Fermi surface. Here we report a pronounced anisotropy in the angle dependence of the interlayer magnetoresistance of the underdoped high transition temperature (high-Tc) superconductor YBa2Cu3O6.58, directly revealing broken C4 symmetry on the Fermi surface. Moreover, we demonstrate that this Fermi surface has C2 symmetry of the type produced by a uniaxial or anisotropic density-wave phase. This establishes the central role of C4 symmetry breaking in the Fermi surface reconstruction of YBa2Cu3O6+δ , and suggests a striking degree of universality among unconventional superconductors.},
  author       = {Ramshaw, B. J. and Harrison, N. and Sebastian, S. E. and Ghannadzadeh, S. and Modic, Kimberly A and Bonn, D. A. and Hardy, W. N. and Liang, Ruixing and Goddard, P. A.},
  issn         = {2397-4648},
  journal      = {npj Quantum Materials},
  number       = {1},
  publisher    = {Springer Nature},
  title        = {{Broken rotational symmetry on the Fermi surface of a high-Tc superconductor}},
  doi          = {10.1038/s41535-017-0013-z},
  volume       = {2},
  year         = {2017},
}

@article{707,
  abstract     = {We answer a question of M. Gromov on the waist of the unit ball.},
  author       = {Akopyan, Arseniy and Karasev, Roman},
  issn         = {0024-6093},
  journal      = {Bulletin of the London Mathematical Society},
  number       = {4},
  pages        = {690 -- 693},
  publisher    = {Wiley},
  title        = {{A tight estimate for the waist of the ball }},
  doi          = {10.1112/blms.12062},
  volume       = {49},
  year         = {2017},
}

@article{708,
  abstract     = {In the developing and adult brain, oligodendrocyte precursor cells (OPCs) are influenced by neuronal activity: they are involved in synaptic signaling with neurons, and their proliferation and differentiation into myelinating glia can be altered by transient changes in neuronal firing. An important question that has been unanswered is whether OPCs can discriminate different patterns of neuronal activity and respond to them in a distinct way. Here, we demonstrate in brain slices that the pattern of neuronal activity determines the functional changes triggered at synapses between axons and OPCs. Furthermore, we show that stimulation of the corpus callosum at different frequencies in vivo affects proliferation and differentiation of OPCs in a dissimilar way. Our findings suggest that neurons do not influence OPCs in “all-or-none” fashion but use their firing pattern to tune the response and behavior of these nonneuronal cells.},
  author       = {Nagy, Balint and Hovhannisyan, Anahit and Barzan, Ruxandra and Chen, Ting and Kukley, Maria},
  issn         = {1544-9173},
  journal      = {PLoS Biology},
  number       = {8},
  publisher    = {Public Library of Science},
  title        = {{Different patterns of neuronal activity trigger distinct responses of oligodendrocyte precursor cells in the corpus callosum}},
  doi          = {10.1371/journal.pbio.2001993},
  volume       = {15},
  year         = {2017},
}

@article{709,
  abstract     = {Adipose tissues play key roles in energy homeostasis. Brown adipocytes and beige adipocytes in white adipose tissue (WAT) share the similar characters of thermogenesis, both of them could be potential targets for obesity management. Several thermo-sensitive transient receptor potential channels (thermoTRPs) are shown to be involved in adipocyte biology. However, the expression pattern of thermoTRPs in adipose tissues from obese mice is still unknown. The mRNA expression of thermoTRPs in subcutaneous WAT (sWAT) and interscapular brown adipose tissue (iBAT) from lean and obese mice were measured using reverse transcriptase-quantitative PCRs (RT-qPCR). The results demonstrated that all 10 thermoTRPs are expressed in both iBAT and sWAT, and without significant difference in the mRNA expression level of thermoTRPs between these two tissues. Moreover, Trpv1 and Trpv3 mRNA expression levels in both iBAT and sWAT were significantly decreased in high fat diet (HFD)-induced obese mice and db/db (leptin receptor deficient) mice. Trpm2 mRNA expression level was significantly decreased only in sWAT from HFD-induced obese mice and db/db mice. On the other hand, Trpv2 and Trpv4 mRNA expression levels in iBAT and sWAT were significantly increased in HFD-induced obese mice and db/db mice. Taken together, we conclude that all 10 thermoTRPs are expressed in iBAT and sWAT. And several thermoTRPs differentially expressed in adipose tissues from HFD-induced obese mice and db/db mice, suggesting a potential involvement in anti-obesity regulations.},
  author       = {Sun, Wuping and Li, Chen and Zhang, Yonghong and Jiang, Changyu and Zhai, Ming-Zhu and Zhou, Qian and Xiao, Lizu and Deng, Qiwen},
  issn         = {1065-6995},
  journal      = {Cell Biology International},
  number       = {8},
  pages        = {908 -- 913},
  publisher    = {Wiley-Blackwell},
  title        = {{Gene expression changes of thermo sensitive transient receptor potential channels in obese mice}},
  doi          = {10.1002/cbin.10783},
  volume       = {41},
  year         = {2017},
}

@inproceedings{710,
  abstract     = {We revisit the problem of estimating entropy of discrete distributions from independent samples, studied recently by Acharya, Orlitsky, Suresh and Tyagi (SODA 2015), improving their upper and lower bounds on the necessary sample size n. For estimating Renyi entropy of order alpha, up to constant accuracy and error probability, we show the following * Upper bounds n = O(1) 2^{(1-1/alpha)H_alpha} for integer alpha&gt;1, as the worst case over distributions with Renyi entropy equal to H_alpha. * Lower bounds n = Omega(1) K^{1-1/alpha} for any real alpha&gt;1, with the constant being an inverse polynomial of the accuracy, as the worst case over all distributions on K elements. Our upper bounds essentially replace the alphabet size by a factor exponential in the entropy, which offers improvements especially in low or medium entropy regimes (interesting for example in anomaly detection). As for the lower bounds, our proof explicitly shows how the complexity depends on both alphabet and accuracy, partially solving the open problem posted in previous works. The argument for upper bounds derives a clean identity for the variance of falling-power sum of a multinomial distribution. Our approach for lower bounds utilizes convex optimization to find a distribution with possibly worse estimation performance, and may be of independent interest as a tool to work with Le Cam’s two point method. },
  author       = {Obremski, Maciej and Skórski, Maciej},
  issn         = {1868-8969},
  location     = {Berkeley, USA},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{Renyi entropy estimation revisited}},
  doi          = {10.4230/LIPIcs.APPROX-RANDOM.2017.20},
  volume       = {81},
  year         = {2017},
}

@inproceedings{711,
  abstract     = {Nested weighted automata (NWA) present a robust and convenient automata-theoretic formalism for quantitative specifications. Previous works have considered NWA that processed input words only in the forward direction. It is natural to allow the automata to process input words backwards as well, for example, to measure the maximal or average time between a response and the preceding request. We therefore introduce and study bidirectional NWA that can process input words in both directions. First, we show that bidirectional NWA can express interesting quantitative properties that are not expressible by forward-only NWA. Second, for the fundamental decision problems of emptiness and universality, we establish decidability and complexity results for the new framework which match the best-known results for the special case of forward-only NWA. Thus, for NWA, the increased expressiveness of bidirectionality is achieved at no additional computational complexity. This is in stark contrast to the unweighted case, where bidirectional finite automata are no more expressive but exponentially more succinct than their forward-only counterparts.},
  author       = {Chatterjee, Krishnendu and Henzinger, Thomas A and Otop, Jan},
  issn         = {1868-8969},
  location     = {Berlin, Germany},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{Bidirectional nested weighted automata}},
  doi          = {10.4230/LIPIcs.CONCUR.2017.5},
  volume       = {85},
  year         = {2017},
}

@article{713,
  abstract     = {To determine the dynamics of allelic-specific expression during mouse development, we analyzed RNA-seq data from 23 F1 tissues from different developmental stages, including 19 female tissues allowing X chromosome inactivation (XCI) escapers to also be detected. We demonstrate that allelic expression arising from genetic or epigenetic differences is highly tissue-specific. We find that tissue-specific strain-biased gene expression may be regulated by tissue-specific enhancers or by post-transcriptional differences in stability between the alleles. We also find that escape from X-inactivation is tissue-specific, with leg muscle showing an unexpectedly high rate of XCI escapers. By surveying a range of tissues during development, and performing extensive validation, we are able to provide a high confidence list of mouse imprinted genes including 18 novel genes. This shows that cluster size varies dynamically during development and can be substantially larger than previously thought, with the Igf2r cluster extending over 10 Mb in placenta.},
  author       = {Andergassen, Daniel and Dotter, Christoph and Wenzel, Dyniel and Sigl, Verena and Bammer, Philipp and Muckenhuber, Markus and Mayer, Daniela and Kulinski, Tomasz and Theussl, Hans and Penninger, Josef and Bock, Christoph and Barlow, Denise and Pauler, Florian and Hudson, Quanah},
  issn         = {2050-084X},
  journal      = {eLife},
  publisher    = {eLife Sciences Publications},
  title        = {{Mapping the mouse Allelome reveals tissue specific regulation of allelic expression}},
  doi          = {10.7554/eLife.25125},
  volume       = {6},
  year         = {2017},
}

@article{715,
  abstract     = {D-cycloserine ameliorates breathing abnormalities and survival rate in a mouse model of Rett syndrome.},
  author       = {Novarino, Gaia},
  issn         = {1946-6234},
  journal      = {Science Translational Medicine},
  number       = {405},
  publisher    = {American Association for the Advancement of Science},
  title        = {{More excitation for Rett syndrome}},
  doi          = {10.1126/scitranslmed.aao4218},
  volume       = {9},
  year         = {2017},
}

@article{716,
  abstract     = {Two-player games on graphs are central in many problems in formal verification and program analysis, such as synthesis and verification of open systems. In this work, we consider solving recursive game graphs (or pushdown game graphs) that model the control flow of sequential programs with recursion.While pushdown games have been studied before with qualitative objectives-such as reachability and ?-regular objectives- in this work, we study for the first time such games with the most well-studied quantitative objective, the mean-payoff objective. In pushdown games, two types of strategies are relevant: (1) global strategies, which depend on the entire global history; and (2) modular strategies, which have only local memory and thus do not depend on the context of invocation but rather only on the history of the current invocation of the module. Our main results are as follows: (1) One-player pushdown games with mean-payoff objectives under global strategies are decidable in polynomial time. (2) Two-player pushdown games with mean-payoff objectives under global strategies are undecidable. (3) One-player pushdown games with mean-payoff objectives under modular strategies are NP-hard. (4) Two-player pushdown games with mean-payoff objectives under modular strategies can be solved in NP (i.e., both one-player and two-player pushdown games with mean-payoff objectives under modular strategies are NP-complete). We also establish the optimal strategy complexity by showing that global strategies for mean-payoff objectives require infinite memory even in one-player pushdown games and memoryless modular strategies are sufficient in two-player pushdown games. Finally, we also show that all the problems have the same complexity if the stack boundedness condition is added, where along with the mean-payoff objective the player must also ensure that the stack height is bounded.},
  author       = {Chatterjee, Krishnendu and Velner, Yaron},
  issn         = {0004-5411},
  journal      = {Journal of the ACM},
  number       = {5},
  pages        = {34},
  publisher    = {ACM},
  title        = {{The complexity of mean-payoff pushdown games}},
  doi          = {10.1145/3121408},
  volume       = {64},
  year         = {2017},
}

