In this paper we prove the following main results:
Theorem A. If bind (G)3/2, thenG–u has a Hamiltonian circuit for every vertexu of graphGi, unlessG belongs either to two classesH1 andH2 of graphs or to some smaller order graphs with |V(G)|17.
Theorem B. If bind (G)3/2 and the maximum degree (G)>(n–1)/2, |V(G)|=n>17, thenG is pancyclic (i.e., it contains a circuit of every lengthm, 3m|V(G)|). 相似文献
Three new compounds, taraxacine-A (1), taraxacine-B (2) and taraxafolin (3) together with twenty-five known compounds, which include two beta-carboline alkaloids, two indole alkaloids, two chlorophylls, two flavonoids, one coumarin, two triterpenoids, one monoterpenoid, one ionone, four steroids and eight benzenoids, were isolated and characterized from the fresh aerial parts of Taraxacum formosanum. Structures of new compounds were determined by spectral analysis. 相似文献
Non-linear standard calibration curves occur frequently in liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS), necessitating the use of non-linear regression curve fitting or a reduction in assay dynamic range. Non-linearity can be minimized by the use of stable isotope internal standards, if the cause of curve bending is ionization saturation. Unfortunately, stable isotope internal standards can be difficult or expensive to synthesize. Structural analog internal standards, if sufficiently close to analytes both in chemical structures and HPLC retention times, may mimic the effect of stable isotope internal standards. Tentative experimental evidence supporting this concept is presented in this paper. 相似文献
N-(α-Benzotriazolylalkyl)arylacetamides, readily available from an arylacetamide, an aldehyde and benzotriazole, undergo intramolecular cyclization under acidic conditions to give 1-aryl-1,4-dihydro-3(2H)-isoquinolinones in good to excellent yields. Similarly, 2-(benzotriazol-1-yl)-2-(o-hydroxyphenyl)ethanols, obtained by lithiation of 2-(benzotriazol-1-ylmethyl)phenols followed by quenching with aldehydes or ketones, eliminate a molecule of water and a molecule of benzotriazole yielding 2-substituted and 2,3-disubstituted benzofurans. 相似文献
The Turán number of a k-uniform hypergraph H,denoted by exk(n;H),is the maximum number of edges in any k-uniform hypergraph F on n vertices which does not contain H as a subgraph.Let Cl~((k)) denote the family of all k-uniform minimal cycles of length l;S(?1,…,?r) denote the family of hypergraphs consisting of unions of r vertex disjoint minimal cycles of length ?1,…?r,respectively,and Cl~((k))denote a k-uniform linear ... 相似文献
Methodology and Computing in Applied Probability - Risk measures for tail risk have an important application in the dynamic portfolio insurance strategies. We propose a new risk measure called... 相似文献
We propose a general framework for solving the group synchronization problem, where we focus on the setting of adversarial or uniform corruption and sufficiently small noise. Specifically, we apply a novel message passing procedure that uses cycle consistency information in order to estimate the corruption levels of group ratios and consequently solve the synchronization problem in our setting. We first explain why the group cycle consistency information is essential for effectively solving group synchronization problems. We then establish exact recovery and linear convergence guarantees for the proposed message passing procedure under a deterministic setting with adversarial corruption. These guarantees hold as long as the ratio of corrupted cycles per edge is bounded by a reasonable constant. We also establish the stability of the proposed procedure to sub-Gaussian noise. We further establish exact recovery with high probability under a common uniform corruption model.