bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypergraph Saturation Irregularities
Authors: Behague Natalie C. 
Published: January 2020

Let $\mathcal{F}$ be a family of $r$-graphs. An $r$-graph $G$ is called $\mathcal{F}$-saturated if it does not contain any members of $\mathcal{F}$ but adding any edge creates a copy of some $r$-graph in $\mathcal{F}$. The saturation number $\operatorname{sat}(\mathcal{F},n)$ is the minimum number of edges in an $\mathcal{F}$-saturated graph on $n$ vertices. We prove that there exists a finite family $\mathcal{F}$ such that $\operatorname{sat}(\mathcal{F},n) / n^{r-1}$ does not tend to a limit. This settles a question of Pikhurko.
Cumulative Subtraction Games
Authors: Cohensius Gal , Larsson Urban , Meir Reshef , Wahlstedt David 
Published: January 2020

We study a variation of Nim-type subtraction games, called Cumulative Subtraction (CS). Two players alternate in removing pebbles out of a joint pile, and their actions add or remove points to a common score. We prove that the zero-sum outcome in optimal play of a CS with a finite number of possible actions is eventually periodic, with period $2s$, where $s$ is the size of the largest available action. This settles a conjecture by Stewart in his Ph.D. thesis (2011). Specifically, we find a quadratic bound, in the size of $s$, on when the outcome function must have become periodic. In case of exactly two possible actions, we give an explicit description of optimal play.
Lattice Homomorphisms Between Weak Orders
Authors: Reading Nathan 
Published: January 2020

We classify surjective lattice homomorphisms $W\to W'$ between the weak orders on finite Coxeter groups. Equivalently, we classify lattice congruences $\Theta$ on $W$ such that the quotient $W/\Theta$ is isomorphic to $W'$. Surprisingly, surjective homomorphisms exist quite generally: They exist if and only if the diagram of $W'$ is obtained from the diagram of $W$ by deleting vertices, deleting edges, and/or decreasing edge labels. A surjective homomorphism $W\to W'$ is determined by its restrictions to rank-two standard parabolic subgroups of $W$. Despite seeming natural in the setting of Coxeter groups, this determination in rank two is nontrivial. Indeed, from the combinatorial lattice theory point of view, all of these classification results should appear unlikely a priori. As an application of the classification of surjective homomorphisms between weak orders, we also obtain a classification of surjective homomorphisms between Cambrian lattices and a general construction of refinement relations between Cambrian fans.
On the Rank of a Random Binary Matrix
Authors: Cooper Colin , Frieze Alan , Pegden Wesley 
Published: January 2020

We study the rank of a random $n \times m$ matrix $\mathbf{A}_{n,m;k}$ with entries from $GF(2)$, and exactly $k$ unit entries in each column, the other entries being zero. The columns are chosen independently and uniformly at random from the set of all ${n \choose k}$ such columns.
We obtain an asymptotically correct estimate for the rank as a function of the number of columns $m$ in terms of $c,n,k$, and where $m=cn/k$. The matrix $\mathbf{A}_{n,m;k}$ forms the vertex-edge incidence matrix of a $k$-uniform random hypergraph $H$. The rank of $\mathbf{A}_{n,m;k}$ can be expressed as follows. Let $|C_2|$ be the number of vertices of the 2-core of $H$, and $|E(C_2)|$ the number of edges. Let $m^*$ be the value of $m$ for which $|C_2|= |E(C_2)|$. Then w.h.p. for $m<m^*$ the rank of $\mathbf{A}_{n,m;k}$ is asymptotic to $m$, and for $m \ge m^*$ the rank is asymptotic to $m-|E(C_2)|+|C_2|$.
In addition, assign i.i.d. $U[0,1]$ weights $X_i, i \in {1,2,...m}$ to the columns, and define the weight of a set of columns $S$ as $X(S)=\sum_{j \in S} X_j$. Define a basis as a set of $n-𝟙 (k\text{ even})$ linearly independent columns. We obtain an asymptotically correct estimate for the minimum weight basis. This generalises the well-known result of Frieze [On the value of a random minimum spanning tree problem, Discrete Applied Mathematics, (1985)] that, for $k=2$, the expected length of a minimum weight spanning tree tends to $\zeta(3)\sim 1.202$.
Latin Cubes with Forbidden Entries
Authors: Casselgren Carl Johan , Markström Klas , Pham Lan Anh 
Published: January 2020

We consider the problem of constructing Latin cubes subject to the condition that some symbols may not appear in certain cells. We prove that there is a constant $\gamma > 0$ such that if $n=2^t$ and $A$ is a $3$-dimensional $n\times n\times n$ array where every cell contains at most $\gamma n$ symbols, and every symbol occurs at most $\gamma n$ times in every line of $A$, then $A$ is avoidable; that is, there is a Latin cube $L$ of order $n$ such that for every $1\leq i,j,k\leq n$, the symbol in position $(i,j,k)$ of $L$ does not appear in the corresponding cell of $A$.
Chromatic Polynomials of Oriented Graphs
Authors: Cox Danielle , Duffy Christopher 
Published: January 2020

The oriented chromatic polynomial of a oriented graph outputs the number of oriented $k$-colourings for any input $k$. We fully classify those oriented graphs for which the oriented graph has the same chromatic polynomial as the underlying simple graph, closing an open problem posed by Sopena. We find that such oriented graphs can be both identified and constructed in polynomial time as they are exactly the family of quasi-transitive oriented co-interval graphs. We study the analytic properties of this polynomial and show that there exist oriented graphs which have chromatic polynomials have roots, including negative real roots, that cannot be realized as the root of any chromatic polynomial of a simple graph.
On the Generalized Spectral Characterizations of Eulerian Graphs
Authors: Qiu Lihong , Ji Yizhe , Wang Wei 
Published: January 2020

A graph $G$ is said to be determined by its generalized spectra (DGS for short) if, for any graph $H$, graphs $H$ and $G$ are cospectral with cospectral complements imply that $H$ is isomorphic to $G$. In Wang (J. Combin. Theory, Ser. B, 122 (2017) 438-451), the author gave a simple method for a graph to be DGS. However, the method does not apply to Eulerian graphs. In this paper, we gave a simple method for a large family of Eulerian graphs to be DGS. Numerical experiments are also presented to illustrate the effectiveness of the proposed method.
New Probabilistic Upper Bounds on the Domination Number of a Graph
Authors: Jafari Rad Nader 
Published: January 2020

A subset $S$ of vertices of a graph $G$ is a dominating set of $G$ if every vertex in $V(G)-S$ has a neighbor in $S$. The domination number $\gamma(G)$ of $G$ is the minimum cardinality of a dominating set of $G$. In this paper, we obtain new (probabilistic) upper bounds for the domination number of a graph, and improve previous bounds given by Arnautov (1974), Payan (1975), and Caro and Roditty (1985) for any graph, and Harant, Pruchnewski and Voigt (1999) for regular graphs.
Matching Complexes of Small Grids
Authors: Matsushita Takahiro 
Published: January 2020

The matching complex $M(G)$ of a simple graph $G$ is the simplicial complex consisting of the matchings on $G$. The matching complex $M(G)$ is isomorphic to the independence complex of the line graph $L(G)$.
Braun and Hough introduced a family of graphs $\Delta^m_n$, which is a generalization of the line graph of the $(n \times 2)$-grid graph. In this paper, we show that the independence complex of $\Delta^m_n$ is a wedge of spheres. This gives an answer to a problem suggested by Braun and Hough.
The Cyclic Sieving Phenomenon on Circular Dyck Paths
Authors: Alexandersson Per , Linusson Svante , Potka Samu 
Published: January 2020

We give a $q$-enumeration of circular Dyck paths, which is a superset of the classical Dyck paths enumerated by the Catalan numbers. These objects have recently been studied by Alexandersson and Panova. Furthermore, we show that this $q$-analogue exhibits the cyclic sieving phenomenon under a natural action of the cyclic group. The enumeration and cyclic sieving is generalized to Möbius paths. We also discuss properties of a generalization of cyclic sieving, which we call subset cyclic sieving, and introduce the notion of Lyndon-like cyclic sieving that concerns special recursive properties of combinatorial objects exhibiting the cyclic sieving phenomenon.
Pengaruh Dana Kampung Terhadap Peningkatan Pembangunan Jalan (Studi Pada Kampung Liman Benawi Kecamatan Trimurjo Kabupaten Lampung Tengah)
Authors: Rohadi Nyono , Mersa Sudarman 
Published: January 2020

Artikel ini membahas tentang pengaruh dana kampong terhadap peningkatan pembangunan jalan. Mengambil studi pada Kampung Liman Benawi Kecamatan Trimurjo Kabupaten Lampung Tengah. Pendekatan penelitian adalah kuantitatif. Menggunakan bantuan instrumen kuisioner, total sampel yang terlibat dalam penelitian ini berjumlah 30 orang responden. Hasil analisis korelasi product moment tersebut di atas didapat nilai X2hitung = 0,547, kemudian dikonsultasikan dengan nilai X2tabel pada taraf nyata 5% = 0,312, sehingga X2hitung > X2tabel pada taraf nyata 5%. Dengan demikian dapat disimpulkan bahwa ada hubungan antara dana Kampung dengan pembangunan jalan lapen di Kampung Liman Benawi Kecamatan Trimurjo Kabupten Lampung Tengah. Sedangkan besarnya pengaruh antara dan Kampung untuk pembangunan jalan lapen sebesar 29,92% (nilai koefisien determinasi).
ORGANIZING RETURN MIGRANT WORKERS FROM INDONESIA FOR SUSTAINABLE GOVERNANCE
Authors: Meiliyana Meiliyana 
Published: January 2020

Artikel ini akan menyajikan pemahaman tentang bagaiamana purna buruh migrant dapat memberikan dampak bagi keluarga dan masyarakat di sekelilingnya dalam hal peningkatan kualitas hidup dan kesejahteraan. Latar belakang utama dari artikel ini adalah semakin mudah dan banyaknya orang yang memutuskan menjadi pekerja migran di luar negaranya sebagai dampak dari globalisasi. Selanjutnya artikel ini akan focus pada purnaburuhmigran dan akan mencoba memberikan penjelasan pentingnya penelitian lebih lanjut tentang bagaimana para purna buruh migrant tersebut dapat berkontribusi untuk pembangunan yang berkelanjutan. Dalam artikel ini disajikan beberapa hasil penelitian tentang hubungan remitan, pembangunan dan buruh migran di dua negara Asia Tenggara yang merupakan negara pengirim buruh migrant terbesar di asiaTenggara. This article presents an understanding of how returnees of overseas workers have an impact on family and community in term of prosperity and wellbeing. The main background of thisarticle is the growing trend of migration as one impact of globalization. Furthermore this article focuses on overseas workers and will seek to address the lack attention of current research on demonstrating how returnees overseas workers could contribute to sustainable development. At the end of the article it suggests to do further research in order to find answers about the impacts of having experiences as overseas workers for family and community prosperity and well being. In this article is discussed two regions in Southeast Asia namely Indonesia and Philippine where in these two countries playing significant role as sending countries for overseas workers.
Singular which, mention-some, and variable scope uniqueness
Authors: Hirsch Aron , Schwarz Bernhard 
Published: January 2020

Singular wh-questions carry a uniqueness presupposition. Dayal (1996) proposed that uniqueness is triggered by an answer operator (ANS), which occurs highest in the question LF, outside the question nucleus. We observe data which we take to show that uniqueness may be triggered at a low scope site, beneath operators which themselves are within the question nucleus. In response to these “low uniqueness” cases, we remove the uniqueness presupposition from ANS, and suggest re-localizing it to the wh itself, which can reconstruct into the question nucleus to take narrow scope. This paves the way for a weakening of ANS previously suggested in Fox (2013) to accommodate mention-some questions.
XO-7 b: A Transiting Hot Jupiter with a Massive Companion on a Wide Orbit
Authors: Crouzet Nicolas , Healy Brian F. , Hébrard Guillaume , McCullough P. R. , Long Doug , Montañés-Rodríguez Pilar , Ribas Ignasi , Vilardell Francesc , Herrero Enrique , Garcia-Melendo Enrique , Conjat Matthieu , Foote Jerry , Garlitz Joe , Vo Phillip , Santos Nuno C. , Bruijne Jos de , Osborn Hugh P. , Dalal Shweta , Nielsen Louise D. 
Published: January 2020

Abstract
Transiting planets orbiting bright stars are the most favorable targets for follow-up and characterization. We report the discovery of the transiting hot Jupiter XO-7 b and of a second, massive companion on a wide orbit around a circumpolar, bright, and metal-rich G0 dwarf (V = 10.52,

,

). We conducted photometric and radial velocity follow-up with a team of amateur and professional astronomers. XO-7 b has a period of

days, a mass of

, a radius of

, a density of

, and an equilibrium temperature of

. Its large atmospheric scale height and the brightness of the host star make it well suited to atmospheric characterization. The wide-orbit companion is detected as a linear trend in radial velocities with an amplitude of

over two years, yielding a minimum mass of 4

; it could be a planet, a brown dwarf, or a low-mass star. The hot Jupiter orbital parameters and the presence of the wide-orbit companion point toward a high-eccentricity migration for the hot Jupiter. Overall, this system will be valuable to understand the atmospheric properties and migration mechanisms of hot Jupiters and will help constrain the formation and evolution models of gas giant exoplanets.
Uranus in Northern Midspring: Persistent Atmospheric Temperatures and Circulations Inferred from Thermal Imaging
Authors: Roman Michael T. , Fletcher Leigh N. , Orton Glenn S. , Rowe-Gurney Naomi , Irwin Patrick G. J. 
Published: January 2020

Abstract
We present results from mid-infrared imaging of Uranus at wavelengths of 13.0 and 18.7 μm, sensing emission from the stratosphere and upper troposphere, acquired using the VISIR instrument at the Very Large Telescope, 2018 September 4–October 20. Using a combination of inverse and forward modeling, we analyze these northern midspring (L

s
∼ 46°) images and compare them to archival data to assess seasonal changes since the 1986 southern solstice and subsequent equinox. We find the data are consistent with little change (<0.3 K) in the upper tropospheric temperature structure, extending the previous conclusions of Orton et al. well past equinox, with only a subtle increase in temperature at the emerging north pole. Additionally, spatial-temporal variations in 13 μm stratospheric emission are investigated for the first time, revealing meridional variation and a hemispheric asymmetry not predicted by models. Finally, we investigate the nature of the stratospheric emission and demonstrate that the observed distribution appears related and potentially coupled to the underlying tropospheric emission six scale heights below. The observations are consistent with either midlatitude heating or an enhanced abundance of acetylene. Considering potential mechanisms and additional observations, we favor a model of acetylene enrichment at midlatitudes resulting from an extension of the upper tropospheric circulation, which appears capable of transporting methane from the troposphere, through the cold trap, and into the stratosphere for subsequent photolysis to acetylene.
Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies*
Authors: Kirby Evan N. , Gilbert Karoline M. , Escala Ivanna , Wojno Jennifer , Guhathakurta Puragra , Majewski Steven R. , Beaton Rachael L. 
Published: January 2020

Abstract
We present deep spectroscopy from Keck/DEIMOS of Andromeda I, III, V, VII, and X, all of which are dwarf spheroidal satellites of M31. The sample includes 256 spectroscopic members across all five dSphs. We confirm previous measurements of the velocity dispersions and dynamical masses, and we provide upper limits on bulk rotation. Our measurements confirm that M31 satellites obey the same relation between stellar mass and stellar metallicity as Milky Way (MW) satellites and other dwarf galaxies in the Local Group. The metallicity distributions show trends with stellar mass that are similar to those of MW satellites, including evidence in massive satellites for external influence, like pre-enrichment or gas accretion. We present the first measurements of individual element ratios, like [Si/Fe], in the M31 system, as well as measurements of the average [α/Fe] ratio. The trends of [α/Fe] with [Fe/H] also follow the same galaxy mass–dependent patterns as MW satellites. Less massive galaxies have more steeply declining slopes of [α/Fe] that begin at lower [Fe/H]. Finally, we compare the chemical evolution of M31 satellites to M31's Giant Stellar Stream and smooth halo. The properties of the M31 system support the theoretical prediction that the inner halo is composed primarily of massive galaxies that were accreted early. As a result, the inner halo exhibits higher [Fe/H] and [α/Fe] than surviving satellite galaxies.
Properties of Local Oscillations in the Lower Sunspot Atmosphere
Authors: Sych Robert , Zhugzhda Yuzef , Yan Xiaoli 
Published: January 2020

Abstract
We present a study of wave processes in the sunspot region NOAA 12670 on 2017 August 10 observed by the Goode Solar Telescope in the TiO 7057 Å and Hα 6563 Å spectral lines. To study the distribution of power oscillations and their dynamics, we applied the pixelized wavelet filtering technique. For the first time, we obtained the spatial structure of oscillation sources as the footpoints of fine magnetic tubes, anchored in the sunspot umbra. We found that at the chromosphere level, the variation of emission is a combination of numerous independent oscillations located in the sources with small angular size. Their spatial shape varies from dots and cells in the umbra to filaments in the penumbra. Each narrow spectral harmonic corresponds to its source, without global correlation among themselves. There is a weak background as low-frequency oscillations distributed over the whole umbra. At the photosphere level we found regions with co-phased broadband oscillations of the whole umbra. Their spectrum includes the ∼3 minutes harmonic, whose maximal value is localized in umbral dots, and the low-frequency part near a period of ∼5 minutes. It is shown that the oscillation sources are displaced at different heights with increasing angular size. We assume that the observed spatial distribution of wave sources indicates the existence of a slow subphotospheric resonator with a vertical magnetic field in the umbra and a wave cutoff frequency due to inclination of the magnetic field line in the penumbra.
Photometric Redshift Estimation with Galaxy Morphology Using Self-organizing Maps
Authors: Wilson Derek , Nayyeri Hooshang , Cooray Asantha , Häußler Boris 
Published: January 2020

Abstract
We use multiband optical and near-infrared photometric observations of galaxies in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey to predict photometric redshifts using artificial neural networks. The multiband observations span from 0.39 to 8.0 μm for a sample of ∼1000 galaxies in the GOODS-S field for which robust size measurements are available from Hubble Space Telescope Wide Field Camera 3 observations. We use self-organizing maps (SOMs) to map the multidimensional photometric and galaxy size observations while taking advantage of existing spectroscopic redshifts at 0 < z < 2 for independent training and testing sets. We show that use of photometric and morphological data led to redshift estimates comparable to redshift measurements from modeling of spectral energy distributions and from SOMs without morphological measurements.
HST/COS Spectra of the Wind Lines of VFTS 102 and 285
Authors: Shepard Katherine , Gies Douglas R. , Lester Kathryn V. , Wang Luqian , Guo Zhao , Kaper Lex , De Koter Alex , Sana Hugues 
Published: January 2020

Abstract
Rapid rotation in massive stars imposes a latitudinal variation in the mass loss from radiatively driven winds that can lead to enhanced mass loss at the poles (with little angular momentum loss) and/or equator (with maximal angular momentum loss). Here we present an examination of the stellar wind lines of the two O-type stars with the fastest known equatorial velocities, VFTS 102 (

km s−1; O9: Vnnne+) and VFTS 285 (

km s−1; O7.5 Vnnn) in the Large Magellanic Cloud. Ultraviolet spectra of both stars were obtained with the Hubble Space Telescope Cosmic Origins Spectrograph. The spectrum of VFTS 285 displays a fast outflow in N v and a much slower wind in Si iv, and we argue that there is a two-wind regime in which mass loss is strong at the poles (fast and tenuous wind) but dominant at the equator (slow and dense winds). These ions and wind lines are not present in the spectrum of the cooler star VFTS 102, but the double-peaked Hα emission in its spectrum implies equatorial mass loss into a circumstellar disk. The results suggest that in the fastest rotating O-stars, most mass is lost as an equatorial outflow, promoting angular momentum loss that contributes to a spin-down over time.
A Catalog of AGN Host Galaxies Observed with HST/ACS: Correlations between Star Formation and AGN Activity
Authors: Stemo Aaron , Comerford Julia M. , Barrows R. Scott , Stern Daniel , Assef Roberto J. , Griffith Roger L. 
Published: January 2020

Abstract
We present the Advanced Camera for Surveys Active Galactic Nuclei (ACS-AGN) Catalog, a catalog of 2585 active galactic nucleus (AGN) host galaxies that are at redshifts 0.2 < z < 2.5 and that were imaged with the Hubble Space Telescope’s Advanced Camera for Surveys (ACS). Using the ACS General Catalog (ACS-GC) as our initial sample, we select an AGN subsample using Spitzer and Chandra data along with their respective established AGN selection criteria. We then gather further multiwavelength photometric data in order to construct spectral energy distributions (SEDs). Using these SEDs, we are able to derive multiple AGN and host galaxy properties, such as star formation rate (SFR), AGN luminosity, stellar mass, and nuclear column density. From these data, we show that AGN host galaxies tend to lie below the star-forming main sequence, with X-ray-selected AGN host galaxies being more offset than IR-selected AGN host galaxies. This suggests that there is some process, possibly negative feedback, in AGN host galaxies causing decreased star formation. We also demonstrate that there is a positive trend between the SFR and AGN luminosity in AGN host galaxies, in individual redshift bins, and across all redshift bins, and that both are correlated with the stellar mass of their galaxies. This points toward an underlying link between the stellar mass, stellar growth, and supermassive black hole growth in a galaxy.