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31.
We solve a problem proposed by Jacobson, Kézdy, and Lehel [4] concerning the existence of forbidden induced subgraph characterizations of line graphs of linear k-uniform hypergraphs with sufficiently large minimal edge-degree. Actually, we prove that for each k3 there is a finite set Z(k) of graphs such that each graph G with minimum edge-degree at least 2k2–3k+1 is the line graph of a linear k-uniform hypergraph if and only if G is a Z(k)-free graph.Acknowledgments. We thank the anonymous referees, whose suggestions helped to improve the presentation of the paper.Winter 2002/2003 DIMACS Award is gratefully acknowledged2000 Mathematics Subject Classification: 05C65 (05C75, 05C85) 相似文献
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34.
Z. T. Alwahabi J. Zetterberg Z. S. Li M. Aldén 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):41-47
High resolution Infrared Polarisation Spectroscopy (IRPS) and Infrared Laser
Induced Fluorescence (IRLIF) techniques were used to probe CO2/N2
binary gas mixture at atmospheric pressure and ambient temperature. The
probed CO2 molecules were prepared by laser excitation to an overtone
and combination ro-vibrational state (1201, J=15) of CO2, centred
at 4988.6612 cm-1. IRPS and IRLIF line profiles were recorded for
several CO2/N2 binary mixtures. The observed IRLIF line shapes
have the expected Lorentzian form while the observed IRPS line shapes are
narrower by a factor of two than those recorded with the IRLIF and appear to
have a Lorentzian-cubed profile. The recorded line profiles provide
measurements of the pressure-broadening coefficient directly at atmospheric
pressure. The Full-Width-Half-Maxima (FWHM) pressure broadening coefficients
are measured, based on IRLIF, to be 0.2174±0.0092 cm-1atm-1 and 0.1327
±0.0077 cm-1atm-1 for self- and N2 collision broadening,
respectively. The broadening coefficients obtained based on IRPS were
measured to be ~8% larger than those obtained with IRLIF. 相似文献
35.
Using results for the distribution of perimeters of random polygons arising from random lines in a plane, we obtain new analytic
approximations to the distributions of areas and local line densities for random polygons and compute various limiting properties
of random polygons. Using simulation, we show that the lengths of adjacent sides of polygons generated by random line processes
in the plane are correlated with ρ=0.616±0.001. 相似文献
36.
H. Tran V. Dana X. Thomas 《Journal of Quantitative Spectroscopy & Radiative Transfer》2007,108(3):342-362
Line intensities are measured for 546 transitions belonging to 13 bands of the main isotopologue 12C2H2 of the acetylene molecule, in the 1.5-μm spectral domain. A multispectrum fitting procedure is used to retrieve line parameters from Fourier transform spectra. Prior to this work, line intensities were known for only 4 bands in this spectral region, from the work of El Hachtouki and Vander Auwera [Absolute line intensities in acetylene: the 1.5 μm region. J Mol Spectrosc 2002;216:355-62]. An excellent agreement is found with the results of these authors, showing that the accuracy of both results is likely better than 1% for the strong bands. However, the spectrum becomes very crowded when one wants to study weaker bands, so that the average accuracy of the intensities reported in the present work is 5%. From these data, vibrational transition dipole moments squared and Herman-Wallis coefficients have been determined for all the bands. 相似文献
37.
A. Predoi-Cross A.V. Unni I. Schofield A.R.W. McKellar 《Journal of Molecular Spectroscopy》2007,245(1):34-51
Transitions of pure carbon dioxide have been measured using a Fourier transform spectrometer in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra, recorded at a resolution of 0.008 cm−1, were analyzed using the Voigt model and a Speed Dependent Voigt line shape model that includes a pressure dependent narrowing parameter. Intensities, self-induced pressure broadening, shifts, and weak line mixing coefficients are determined. The results obtained are consistent with other studies in addition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxation matrix elements. 相似文献
38.
Daryl Geller Domenico Marinucci 《Journal of Mathematical Analysis and Applications》2011,375(2):610-630
The construction of needlet-type wavelets on sections of the spin line bundles over the sphere has been recently addressed in Geller and Marinucci (2008) [14], and Geller et al. (2008, 2009) [12] and [13]. Here we focus on an alternative proposal for needlets on this spin line bundle, in which needlet coefficients arise from the usual, rather than the spin, spherical harmonics, as in the previous constructions. We label this system mixed needlets and investigate in full their properties, including localization, the exact tight frame characterization, reconstruction formula, decomposition of functional spaces, and asymptotic uncorrelation in the stochastic case. We outline astrophysical applications. 相似文献
39.
40.
John A. Ford Yasushi Narushima Hiroshi Yabe 《Computational Optimization and Applications》2008,40(2):191-216
Conjugate gradient methods are appealing for large scale nonlinear optimization problems, because they avoid the storage of
matrices. Recently, seeking fast convergence of these methods, Dai and Liao (Appl. Math. Optim. 43:87–101, 2001) proposed a conjugate gradient method based on the secant condition of quasi-Newton methods, and later Yabe and Takano (Comput.
Optim. Appl. 28:203–225, 2004) proposed another conjugate gradient method based on the modified secant condition. In this paper, we make use of a multi-step
secant condition given by Ford and Moghrabi (Optim. Methods Softw. 2:357–370, 1993; J. Comput. Appl. Math. 50:305–323, 1994) and propose two new conjugate gradient methods based on this condition. The methods are shown to be globally convergent
under certain assumptions. Numerical results are reported. 相似文献