@article{383,
  abstract     = {In the quest for more efficient thermoelectric material able to convert thermal to electrical energy and vice versa, composites that combine a semiconductor host having a large Seebeck coefficient with metal nanodomains that provide phonon scattering and free charge carriers are particularly appealing. Here, we present our experimental results on the thermal and electrical transport properties of PbS-metal composites produced by a versatile particle blending procedure, and where the metal work function allows injecting electrons to the intrinsic PbS host. We compare the thermoelectric performance of composites with microcrystalline or nanocrystalline structures. The electrical conductivity of the microcrystalline host can be increased several orders of magnitude with the metal inclusion, while relatively high Seebeck coefficient can be simultaneously conserved. On the other hand, in nanostructured materials, the host crystallites are not able to sustain a band bending at its interface with the metal, becoming flooded with electrons. This translates into even higher electrical conductivities than the microcrystalline material, but at the expense of lower Seebeck coefficient values.},
  author       = {Liu, Yu and Cadavid, Doris and Ibanez Sabate, Maria and Ortega, Silvia and Márti Sánchez, Sara and Dobrozhan, Oleksander and Kovalenko, Maksym and Arbiol, Jordi and Cabot, Andreu},
  journal      = {Applied Physics Letters},
  publisher    = {American Institute of Physics},
  title        = {{Thermoelectric properties of semiconductor-metal composites produced by particle blending}},
  doi          = {https://doi.org/10.1063/1.4961679},
  volume       = {4},
  year         = {2016},
}

@article{389,
  abstract     = {The coherent optical manipulation of solids is emerging as a promising way to engineer novel quantum states of matter. The strong time-periodic potential of intense laser light can be used to generate hybrid photon-electron states. Interaction of light with Bloch states leads to Floquet-Bloch states, which are essential in realizing new photo-induced quantum phases. Similarly, dressing of free-electron states near the surface of a solid generates Volkov states, which are used to study nonlinear optics in atoms and semiconductors. The interaction of these two dynamic states with each other remains an open experimental problem. Here we use time- and angle-resolved photoemission spectroscopy (Tr-ARPES) to selectively study the transition between these two states on the surface of the topological insulator Bi2Se3. We find that the coupling between the two strongly depends on the electron momentum, providing a route to enhance or inhibit it. Moreover, by controlling the light polarization we can negate Volkov states to generate pure Floquet-Bloch states. This work establishes a systematic path for the coherent manipulation of solids via light-matter interaction.},
  author       = {Mahmood, Fahad and Chan, Ching and Alpichshev, Zhanybek and Gardner, Dillon and Lee, Young and Lee, Patrick and Gedik, Nuh},
  journal      = {Nature Physics},
  number       = {4},
  pages        = {306 -- 310},
  publisher    = {Nature Publishing Group},
  title        = {{Selective scattering between Floquet Bloch and Volkov states in a topological insulator}},
  doi          = {10.1038/nphys3609},
  volume       = {12},
  year         = {2016},
}

@article{390,
  abstract     = {In the underdoped copper-oxides, high-temperature superconductivity condenses from a nonconventional metallic "pseudogap" phase that exhibits a variety of non-Fermi liquid properties. Recently, it has become clear that a charge density wave (CDW) phase exists within the pseudogap regime. This CDW coexists and competes with superconductivity (SC) below the transition temperature Tc, suggesting that these two orders are intimately related. Here we show that the condensation of the superfluid from this unconventional precursor is reflected in deviations from the predictions of BSC theory regarding the recombination rate of quasiparticles. We report a detailed investigation of the quasiparticle (QP) recombination lifetime, τqp, as a function of temperature and magnetic field in underdoped HgBa2CuO4+δ (Hg-1201) and YBa2Cu3O6+x (YBCO) single crystals by ultrafast time-resolved reflectivity. We find that τqp (T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field. We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below. Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.},
  author       = {Hinton, James and Thewalt, E and Alpichshev, Zhanybek and Mahmood, Fahad and Koralek, Jake and Chan, Mun and Veit, Michael and Dorow, Chelsey and Barišić, Neven and Kemper, Alexander and Bonn, Doug and Hardy, Walter and Liang, Ruixing and Gedik, Nuh and Greven, Martin and Lanzara, Alessandra and Orenstein, Joseph},
  journal      = {Scientific Reports},
  publisher    = {Nature Publishing Group},
  title        = {{The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors}},
  doi          = {10.1038/srep23610},
  volume       = {6},
  year         = {2016},
}

@article{1321,
  abstract     = {Most migrating cells extrude their front by the force of actin polymerization. Polymerization requires an initial nucleation step, which is mediated by factors establishing either parallel filaments in the case of filopodia or branched filaments that form the branched lamellipodial network. Branches are considered essential for regular cell motility and are initiated by the Arp2/3 complex, which in turn is activated by nucleation-promoting factors of the WASP and WAVE families. Here we employed rapid amoeboid crawling leukocytes and found that deletion of the WAVE complex eliminated actin branching and thus lamellipodia formation. The cells were left with parallel filaments at the leading edge, which translated, depending on the differentiation status of the cell, into a unipolar pointed cell shape or cells with multiple filopodia. Remarkably, unipolar cells migrated with increased speed and enormous directional persistence, while they were unable to turn towards chemotactic gradients. Cells with multiple filopodia retained chemotactic activity but their migration was progressively impaired with increasing geometrical complexity of the extracellular environment. These findings establish that diversified leading edge protrusions serve as explorative structures while they slow down actual locomotion.},
  author       = {Leithner, Alexander F and Eichner, Alexander and Müller, Jan and Reversat, Anne and Brown, Markus and Schwarz, Jan and Merrin, Jack and De Gorter, David and Schur, Florian and Bayerl, Jonathan and De Vries, Ingrid and Wieser, Stefan and Hauschild, Robert and Lai, Frank and Moser, Markus and Kerjaschki, Dontscho and Rottner, Klemens and Small, Victor and Stradal, Theresia and Sixt, Michael K},
  journal      = {Nature Cell Biology},
  pages        = {1253 -- 1259},
  publisher    = {Nature Publishing Group},
  title        = {{Diversified actin protrusions promote environmental exploration but are dispensable for locomotion of leukocytes}},
  doi          = {10.1038/ncb3426},
  volume       = {18},
  year         = {2016},
}

@inproceedings{1437,
  abstract     = {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.},
  author       = {Chatterjee, Krishnendu and Goharshady, Amir and Ibsen-Jensen, Rasmus and Pavlogiannis, Andreas},
  location     = {St. Petersburg, FL, USA},
  pages        = {733 -- 747},
  publisher    = {ACM},
  title        = {{Algorithms for algebraic path properties in concurrent systems of constant treewidth components}},
  doi          = {10.1145/2837614.2837624},
  volume       = {20-22},
  year         = {2016},
}

@inproceedings{1386,
  abstract     = {We consider nondeterministic probabilistic programs with the most basic liveness property of termination. We present efficient methods for termination analysis of nondeterministic probabilistic programs with polynomial guards and assignments. Our approach is through synthesis of polynomial ranking supermartingales, that on one hand significantly generalizes linear ranking supermartingales and on the other hand is a counterpart of polynomial ranking-functions for proving termination of nonprobabilistic programs. The approach synthesizes polynomial ranking-supermartingales through Positivstellensatz's, yielding an efficient method which is not only sound, but also semi-complete over a large subclass of programs. We show experimental results to demonstrate that our approach can handle several classical programs with complex polynomial guards and assignments, and can synthesize efficient quadratic ranking-supermartingales when a linear one does not exist even for simple affine programs.},
  author       = {Chatterjee, Krishnendu and Fu, Hongfei and Goharshady, Amir},
  location     = {Toronto, Canada},
  pages        = {3 -- 22},
  publisher    = {Springer},
  title        = {{Termination analysis of probabilistic programs through Positivstellensatz's}},
  doi          = {10.1007/978-3-319-41528-4_1},
  volume       = {9779},
  year         = {2016},
}

@article{1100,
  abstract     = {During metazoan development, the temporal pattern of morphogen signaling is critical for organizing cell fates in space and time. Yet, tools for temporally controlling morphogen signaling within the embryo are still scarce. Here, we developed a photoactivatable Nodal receptor to determine how the temporal pattern of Nodal signaling affects cell fate specification during zebrafish gastrulation. By using this receptor to manipulate the duration of Nodal signaling in vivo by light, we show that extended Nodal signaling within the organizer promotes prechordal plate specification and suppresses endoderm differentiation. Endoderm differentiation is suppressed by extended Nodal signaling inducing expression of the transcriptional repressor goosecoid (gsc) in prechordal plate progenitors, which in turn restrains Nodal signaling from upregulating the endoderm differentiation gene sox17 within these cells. Thus, optogenetic manipulation of Nodal signaling identifies a critical role of Nodal signaling duration for organizer cell fate specification during gastrulation.},
  author       = {Sako, Keisuke and Pradhan, Saurabh and Barone, Vanessa and Inglés Prieto, Álvaro and Mueller, Patrick and Ruprecht, Verena and Capek, Daniel and Galande, Sanjeev and Janovjak, Harald L and Heisenberg, Carl-Philipp J},
  journal      = {Cell Reports},
  number       = {3},
  pages        = {866 -- 877},
  publisher    = {Cell Press},
  title        = {{Optogenetic control of nodal signaling reveals a temporal pattern of nodal signaling regulating cell fate specification during gastrulation}},
  doi          = {10.1016/j.celrep.2016.06.036},
  volume       = {16},
  year         = {2016},
}

@article{1183,
  abstract     = {Autism spectrum disorders (ASD) are a group of genetic disorders often overlapping with other neurological conditions. We previously described abnormalities in the branched-chain amino acid (BCAA) catabolic pathway as a cause of ASD. Here, we show that the solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. In mice, deletion of Slc7a5 from the endothelial cells of the BBB leads to atypical brain amino acid profile, abnormal mRNA translation, and severe neurological abnormalities. Furthermore, we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene. Finally, we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice. Our data elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA in human brain function.},
  author       = {Tarlungeanu, Dora-Clara and Deliu, Elena and Dotter, Christoph and Kara, Majdi and Janiesch, Philipp and Scalise, Mariafrancesca and Galluccio, Michele and Tesulov, Mateja and Morelli, Emanuela and Sönmez, Fatma and Bilgüvar, Kaya and Ohgaki, Ryuichi and Kanai, Yoshikatsu and Johansen, Anide and Esharif, Seham and Ben Omran, Tawfeg and Topcu, Meral and Schlessinger, Avner and Indiveri, Cesare and Duncan, Kent and Caglayan, Ahmet and Günel, Murat and Gleeson, Joseph and Novarino, Gaia},
  journal      = {Cell},
  number       = {6},
  pages        = {1481 -- 1494},
  publisher    = {Cell Press},
  title        = {{Impaired amino acid transport at the blood brain barrier is a cause of autism spectrum disorder}},
  doi          = {10.1016/j.cell.2016.11.013},
  volume       = {167},
  year         = {2016},
}

@article{11519,
  abstract     = {Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6–7). However, observations from a very large (∼5 deg2) Lyα narrow-band survey at z = 6.6 show that this is not the case for the most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up observations of the two most luminous Lyα candidates in the COSMOS field: “MASOSA” and “CR7.” We used X-SHOOTER, SINFONI, and FORS2 on the Very Large Telescope, and DEIMOS on Keck, to confirm both candidates beyond any doubt. We find redshifts of z = 6.541 and z = 6.604 for “MASOSA” and “CR7,” respectively. MASOSA has a strong detection in Lyα with a line width of 386 ± 30 km s−1 (FWHM) and with very high EW0 (>200 Å), but undetected in the continuum, implying very low stellar mass and a likely young, metal-poor stellar population. “CR7,” with an observed Lyα luminosity of 1043.92±0.05 erg s−1 is the most luminous Lyα emitter ever found at z > 6 and is spatially extended (∼16 kpc). “CR7” reveals a narrow Lyα line with 266 ± 15 km s−1 FWHM, being detected in the near-infrared (NIR) (rest-frame UV; β = −2.3 ± 0.1) and in IRAC/Spitzer. We detect a narrow He II 1640 Å emission line (6σ, FWHM = 130 ± 30 km s−1 ) in CR7 which can explain the clear excess seen in the J-band photometry (EW0 ∼ 80 Å). We find no other emission lines from the UV to the NIR in our X-SHOOTER spectra (He II/O III] 1663 Å > 3 and He II/C III] 1908 Å > 2.5). We conclude that CR7 is best explained by a combination of a PopIII-like population, which dominates the rest-frame UV and the nebular emission, and a more normal stellar population, which presumably dominates the mass. Hubble Space Telescope/WFC3 observations show that the light is indeed spatially separated between a very blue component, coincident with Lyα and He II emission, and two red components (∼5 kpc away), which dominate the mass. Our findings are consistent with theoretical predictions of a PopIII wave, with PopIII star formation migrating away from the original sites of star formation.},
  author       = {Sobral, David and Matthee, Jorryt J and Darvish, Behnam and Schaerer, Daniel and Mobasher, Bahram and Röttgering, Huub and Santos, Sérgio and Hemmati, Shoubaneh},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, dark ages, reionization, first stars – early universe – galaxies: evolution},
  number       = {2},
  pages        = {139},
  publisher    = {IOP Publishing},
  title        = {{Evidence for PopIII-like stellar populations in the most luminous Lyα emitters at the epoch of reionisation: Spectroscopic confirmation}},
  doi          = {10.1088/0004-637X/808/2/139},
  volume       = {808},
  year         = {2015},
}

@article{11579,
  abstract     = {CR7 is the brightest z = 6.6 Ly α emitter (LAE) known to date, and spectroscopic follow-up by Sobral et al. suggests that CR7 might host Population (Pop) III stars. We examine this interpretation using cosmological hydrodynamical simulations. Several simulated galaxies show the same ‘Pop III wave’ pattern observed in CR7. However, to reproduce the extreme CR7 Ly α/He II1640 line luminosities (⁠Lα/HeII⁠) a top-heavy initial mass function and a massive ( ≳ 107 M⊙) Pop III burst with age ≲ 2 Myr are required. Assuming that the observed properties of Ly α and He II emission are typical for Pop III, we predict that in the COSMOS/UDS/SA22 fields, 14 out of the 30 LAEs at z = 6.6 with Lα > 1043.3 erg s−1 should also host Pop III stars producing an observable LHeII≳1042.7ergs−1⁠. As an alternate explanation, we explore the possibility that CR7 is instead powered by accretion on to a direct collapse black hole. Our model predicts Lα, LHeII⁠, and X-ray luminosities that are in agreement with the observations. In any case, the observed properties of CR7 indicate that this galaxy is most likely powered by sources formed from pristine gas. We propose that further X-ray observations can distinguish between the two above scenarios.},
  author       = {Pallottini, A. and Ferrara, A. and Pacucci, F. and Gallerani, S. and Salvadori, S. and Schneider, R. and Schaerer, D. and Sobral, D. and Matthee, Jorryt J},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, black hole physics, stars: Population III, galaxies: high-redshift},
  number       = {3},
  pages        = {2465--2470},
  publisher    = {Oxford University Press},
  title        = {{The brightest Lyα emitter: Pop III or black hole?}},
  doi          = {10.1093/mnras/stv1795},
  volume       = {453},
  year         = {2015},
}

@article{11580,
  abstract     = {We present results from the largest contiguous narrow-band survey in the near-infrared. We have used the wide-field infrared camera/Canada–France–Hawaii Telescope and the lowOH2 filter (1.187 ± 0.005 μm) to survey ≈10 deg2 of contiguous extragalactic sky in the SA22 field. A total of ∼6000 candidate emission-line galaxies are found. We use deep ugrizJK data to obtain robust photometric redshifts. We combine our data with the High-redshift(Z) Emission Line Survey (HiZELS), explore spectroscopic surveys (VVDS, VIPERS) and obtain our own spectroscopic follow-up with KMOS, FMOS and MOSFIRE to derive large samples of high-redshift emission-line selected galaxies: 3471 Hα emitters at z = 0.8, 1343 [O III] + Hβ emitters at z = 1.4 and 572 [O II] emitters at z = 2.2. We probe comoving volumes of >106 Mpc3 and find significant overdensities, including an 8.5σ (spectroscopically confirmed) overdensity of Hα emitters at z = 0.81. We derive Hα, [O III] + Hβ and [O II] luminosity functions at z = 0.8, 1.4, 2.2, respectively, and present implications for future surveys such as Euclid. Our uniquely large volumes/areas allow us to subdivide the samples in thousands of randomized combinations of areas and provide a robust empirical measurement of sample/cosmic variance. We show that surveys for star-forming/emission-line galaxies at a depth similar to ours can only overcome cosmic-variance (errors <10 per cent) if they are based on volumes >5 × 105 Mpc3; errors on L* and ϕ* due to sample (cosmic) variance on surveys probing ∼104 and ∼105 Mpc3 are typically very high: ∼300 and ∼40–60 per cent, respectively.},
  author       = {Sobral, D. and Matthee, Jorryt J and Best, P. N. and Smail, I. and Khostovan, A. A. and Milvang-Jensen, B. and Kim, J.-W. and Stott, J. and Calhau, J. and Nayyeri, H. and Mobasher, B.},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: formation, galaxies: luminosity function, mass function, cosmology: observations, early Universe, large-scale structure of Universe},
  number       = {3},
  pages        = {2303--2323},
  publisher    = {Oxford University Press},
  title        = {{CF-HiZELS, an ∼10 deg2 emission-line survey with spectroscopic follow-up: Hα, [O III] + Hβ and [O II] luminosity functions at z = 0.8, 1.4 and 2.2 }},
  doi          = {10.1093/mnras/stv1076},
  volume       = {451},
  year         = {2015},
}

@article{11581,
  abstract     = {Using wide-field narrow-band surveys, we provide a new measurement of the z = 6.6 Lymanα emitter (LAE) luminosity function (LF), which constraints the bright end for the first time. We use a combination of archival narrow-band NB921 data in UDS and new NB921 measurements in SA22 and COSMOS/UltraVISTA, all observed with the Subaru telescope, with a total area of ∼5 deg2. We exclude lower redshift interlopers by using broad-band optical and near-infrared photometry and also exclude three supernovae with data split over multiple epochs. Combining the UDS and COSMOS samples, we find no evolution of the bright end of the Lyα LF between z = 5.7 and 6.6, which is supported by spectroscopic follow-up, and conclude that sources with Himiko-like luminosity are not as rare as previously thought, with number densities of ∼1.5 × 10−5 Mpc−3. Combined with our wide-field SA22 measurements, our results indicate a non-Schechter-like bright end of the LF at z = 6.6 and a different evolution of observed faint and bright LAEs, overcoming cosmic variance. This differential evolution is also seen in the spectroscopic follow-up of UV-selected galaxies and is now also confirmed for LAEs, and we argue that it may be an effect of reionization. Using a toy model, we show that such differential evolution of the LF is expected, since brighter sources are able to ionize their surroundings earlier, such that Lyα photons are able to escape. Our targets are excellent candidates for detailed follow-up studies and provide the possibility to give a unique view on the earliest stages in the formation of galaxies and reionization process.},
  author       = {Matthee, Jorryt J and Sobral, David and Santos, Sérgio and Röttgering, Huub and Darvish, Behnam and Mobasher, Bahram},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  number       = {1},
  pages        = {400--417},
  publisher    = {Oxford University Press},
  title        = {{Identification of the brightest Lyα emitters at z = 6.6: implications for the evolution of the luminosity function in the reionization era}},
  doi          = {10.1093/mnras/stv947},
  volume       = {451},
  year         = {2015},
}

@article{11668,
  abstract     = {We study multiple keyword sponsored search auctions with budgets. Each keyword has multiple ad slots with a click-through rate. The bidders have additive valuations, which are linear in the click-through rates, and budgets, which are restricting their overall payments. Additionally, the number of slots per keyword assigned to a bidder is bounded.

We show the following results: (1) We give the first mechanism for multiple keywords, where click-through rates differ among slots. Our mechanism is incentive compatible in expectation, individually rational in expectation, and Pareto optimal. (2) We study the combinatorial setting, where each bidder is only interested in a subset of the keywords. We give an incentive compatible, individually rational, Pareto-optimal, and deterministic mechanism for identical click-through rates. (3) We give an impossibility result for incentive compatible, individually rational, Pareto-optimal, and deterministic mechanisms for bidders with diminishing marginal valuations.},
  author       = {Colini-Baldeschi, Riccardo and Leonardi, Stefano and Henzinger, Monika H and Starnberger, Martin},
  issn         = {2167-8383},
  journal      = {ACM Transactions on Economics and Computation},
  keywords     = {Algorithms, Economics, Clinching ascending auction, auctions with budgets, Sponsored search auctions},
  number       = {1},
  publisher    = {Association for Computing Machinery},
  title        = {{On multiple keyword sponsored search auctions with budgets}},
  doi          = {10.1145/2818357},
  volume       = {4},
  year         = {2015},
}

@article{11669,
  abstract     = {We study individual rational, Pareto-optimal, and incentive compatible mechanisms for auctions with heterogeneous items and budget limits. We consider settings with multiunit demand and additive valuations. For single-dimensional valuations we prove a positive result for randomized mechanisms, and a negative result for deterministic mechanisms. While the positive result allows for private budgets, the negative result is for public budgets. For multidimensional valuations and public budgets we prove an impossibility result that applies to deterministic and randomized mechanisms. Taken together this shows the power of randomization in certain settings with heterogeneous items, but it also shows its limitations.},
  author       = {Dütting, Paul and Henzinger, Monika H and Starnberger, Martin},
  issn         = {2167-8383},
  journal      = {ACM Transactions on Economics and Computation},
  keywords     = {Algorithmic game theory, auction theory, Clinching auction, Pareto optimality, Budget limits},
  number       = {1},
  publisher    = {Association for Computing Machinery},
  title        = {{Auctions for heterogeneous items and budget limits}},
  doi          = {10.1145/2818351},
  volume       = {4},
  year         = {2015},
}

@article{11670,
  abstract     = {Auctions are widely used on the Web. Applications range from sponsored search to platforms such as eBay. In these and in many other applications the auctions in use are single-/multi-item auctions with unit demand. The main drawback of standard mechanisms for this type of auctions, such as VCG and GSP, is the limited expressiveness that they offer to the bidders. The General Auction Mechanism (GAM) of Aggarwal et al. [2009] takes a first step toward addressing the problem of limited expressiveness by computing a bidder optimal, envy-free outcome for linear utility functions with identical slopes and a single discontinuity per bidder-item pair. We show that in many practical situations this does not suffice to adequately model the preferences of the bidders, and we overcome this problem by presenting the first mechanism for piecewise linear utility functions with nonidentical slopes and multiple discontinuities. Our mechanism runs in polynomial time. Like GAM it is incentive compatible for inputs that fulfill a certain nondegeneracy assumption, but our requirement is more general than the requirement of GAM. For discontinuous utility functions that are nondegenerate as well as for continuous utility functions the outcome of our mechanism is a competitive equilibrium. We also show how our mechanism can be used to compute approximately bidder optimal, envy-free outcomes for a general class of continuous utility functions via piecewise linear approximation. Finally, we prove hardness results for even more expressive settings.},
  author       = {Dütting, Paul and Henzinger, Monika H and Weber, Ingmar},
  issn         = {2167-8383},
  journal      = {ACM Transactions on Economics and Computation},
  keywords     = {Computational Mathematics, Marketing, Economics and Econometrics, Statistics and Probability, Computer Science (miscellaneous)},
  number       = {1},
  publisher    = {Association for Computing Machinery},
  title        = {{An expressive mechanism for auctions on the web}},
  doi          = {10.1145/2716312},
  volume       = {4},
  year         = {2015},
}

@inproceedings{11773,
  abstract     = {Ad exchanges are an emerging platform for trading advertisement slots on the web with billions of dollars revenue per year. Every time a user visits a web page, the publisher of that web page can ask an ad exchange to auction off the ad slots on this page to determine which advertisements are shown at which price. Due to the high volume of traffic, ad networks typically act as mediators for individual advertisers at ad exchanges. If multiple advertisers in an ad network are interested in the ad slots of the same auction, the ad network might use a “local” auction to resell the obtained ad slots among its advertisers.

In this work we want to deepen the theoretical understanding of these new markets by analyzing them from the viewpoint of combinatorial auctions. Prior work studied mostly single-item auctions, while we allow the advertisers to express richer preferences over multiple items. We develop a game-theoretic model for the entanglement of the central auction at the ad exchange with the local auctions at the ad networks. We consider the incentives of all three involved parties and suggest a three-party competitive equilibrium, an extension of the Walrasian equilibrium that ensures envy-freeness for all participants. We show the existence of a three-party competitive equilibrium and a polynomial-time algorithm to find one for gross-substitute bidder valuations.},
  author       = {Ben-Zwi, Oren and Henzinger, Monika H and Loitzenbauer, Veronika},
  booktitle    = {11th International Conference on Web and Internet Economics},
  isbn         = {9783662489949},
  issn         = {0302-9743},
  location     = {Amsterdam, Netherlands},
  pages        = {104–117},
  publisher    = {Springer Nature},
  title        = {{Ad exchange: Envy-free auctions with mediators}},
  doi          = {10.1007/978-3-662-48995-6_8},
  volume       = {9470},
  year         = {2015},
}

@inproceedings{11774,
  abstract     = {Combinatorial auctions (CA) are a well-studied area in algorithmic mechanism design. However, contrary to the standard model, empirical studies suggest that a bidder’s valuation often does not depend solely on the goods assigned to him. For instance, in adwords auctions an advertiser might not want his ads to be displayed next to his competitors’ ads. In this paper, we propose and analyze several natural graph-theoretic models that incorporate such negative externalities, in which bidders form a directed conflict graph with maximum out-degree Δ. We design algorithms and truthful mechanisms for social welfare maximization that attain approximation ratios depending on Δ.

For CA, our results are twofold: (1) A lottery that eliminates conflicts by discarding bidders/items independent of the bids. It allows to apply any truthful 𝛼-approximation mechanism for conflict-free valuations and yields an 𝒪(𝛼Δ)-approximation mechanism. (2) For fractionally sub-additive valuations, we design a rounding algorithm via a novel combination of a semi-definite program and a linear program, resulting in a cone program; the approximation ratio is 𝒪((ΔloglogΔ)/logΔ). The ratios are almost optimal given existing hardness results.

For adwords auctions, we present several algorithms for the most relevant scenario when the number of items is small. In particular, we design a truthful mechanism with approximation ratio 𝑜(Δ) when the number of items is only logarithmic in the number of bidders.},
  author       = {Cheung, Yun Kuen and Henzinger, Monika H and Hoefer, Martin and Starnberger, Martin},
  booktitle    = {11th International Conference on Web and Internet Economics},
  isbn         = {9783662489949},
  issn         = {0302-9743},
  location     = {Amsterdam, Netherlands},
  pages        = {230–243},
  publisher    = {Springer Nature},
  title        = {{Combinatorial auctions with conflict-based externalities}},
  doi          = {10.1007/978-3-662-48995-6_17},
  volume       = {9470},
  year         = {2015},
}

@inproceedings{11785,
  abstract     = {Recently we presented the first algorithm for maintaining the set of nodes reachable from a source node in a directed graph that is modified by edge deletions with 𝑜(𝑚𝑛) total update time, where 𝑚 is the number of edges and 𝑛 is the number of nodes in the graph [Henzinger et al. STOC 2014]. The algorithm is a combination of several different algorithms, each for a different 𝑚 vs. 𝑛 trade-off. For the case of 𝑚=Θ(𝑛1.5) the running time is 𝑂(𝑛2.47), just barely below 𝑚𝑛=Θ(𝑛2.5). In this paper we simplify the previous algorithm using new algorithmic ideas and achieve an improved running time of 𝑂̃ (min(𝑚7/6𝑛2/3,𝑚3/4𝑛5/4+𝑜(1),𝑚2/3𝑛4/3+𝑜(1)+𝑚3/7𝑛12/7+𝑜(1))). This gives, e.g., 𝑂(𝑛2.36) for the notorious case 𝑚=Θ(𝑛1.5). We obtain the same upper bounds for the problem of maintaining the strongly connected components of a directed graph undergoing edge deletions. Our algorithms are correct with high probabililty against an oblivious adversary.},
  author       = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon},
  booktitle    = {42nd International Colloquium on Automata, Languages and Programming},
  isbn         = {9783662476710},
  issn         = {0302-9743},
  location     = {Kyoto, Japan},
  pages        = {725 -- 736},
  publisher    = {Springer Nature},
  title        = {{Improved algorithms for decremental single-source reachability on directed graphs}},
  doi          = {10.1007/978-3-662-47672-7_59},
  volume       = {9134},
  year         = {2015},
}

@inproceedings{11786,
  abstract     = {In this paper, we develop a dynamic version of the primal-dual method for optimization problems, and apply it to obtain the following results. (1) For the dynamic set-cover problem, we maintain an 𝑂(𝑓2)-approximately optimal solution in 𝑂(𝑓⋅log(𝑚+𝑛)) amortized update time, where 𝑓 is the maximum “frequency” of an element, 𝑛 is the number of sets, and 𝑚 is the maximum number of elements in the universe at any point in time. (2) For the dynamic 𝑏-matching problem, we maintain an 𝑂(1)-approximately optimal solution in 𝑂(log3𝑛) amortized update time, where 𝑛 is the number of nodes in the graph.},
  author       = {Bhattacharya, Sayan and Henzinger, Monika H and Italiano, Giuseppe F.},
  booktitle    = {42nd International Colloquium on Automata, Languages and Programming},
  isbn         = {9783662476710},
  issn         = {0302-9743},
  location     = {Kyoto, Japan},
  pages        = {206 -- 218},
  publisher    = {Springer Nature},
  title        = {{Design of dynamic algorithms via primal-dual method}},
  doi          = {10.1007/978-3-662-47672-7_17},
  volume       = {9134},
  year         = {2015},
}

@inproceedings{11787,
  abstract     = {We present faster algorithms for computing the 2-edge and 2-vertex strongly connected components of a directed graph. While in undirected graphs the 2-edge and 2-vertex connected components can be found in linear time, in directed graphs with m edges and n vertices only rather simple O(m n)-time algorithms were known. We use a hierarchical sparsification technique to obtain algorithms that run in time 𝑂(𝑛2). For 2-edge strongly connected components our algorithm gives the first running time improvement in 20 years. Additionally we present an 𝑂(𝑚2/log𝑛)-time algorithm for 2-edge strongly connected components, and thus improve over the O(m n) running time also when 𝑚=𝑂(𝑛). Our approach extends to k-edge and k-vertex strongly connected components for any constant k with a running time of 𝑂(𝑛2log𝑛) for k-edge-connectivity and 𝑂(𝑛3) for k-vertex-connectivity.},
  author       = {Henzinger, Monika H and Krinninger, Sebastian and Loitzenbauer, Veronika},
  booktitle    = {2nd International Colloquium on Automata, Languages and Programming},
  isbn         = {9783662476710},
  issn         = {0302-9743},
  location     = {Kyoto, Japan},
  pages        = {713 -- 724},
  publisher    = {Springer Nature},
  title        = {{Finding 2-edge and 2-vertex strongly connected components in quadratic time}},
  doi          = {10.1007/978-3-662-47672-7_58},
  volume       = {9134},
  year         = {2015},
}