This is in general a hard problem The problem is NP complete Knuth cf even if we restrict ourselves to planar undirected graphs Lynch assuming that k is variable On the other hand it is a deep result of Robertson and Seymour that for each xed k the problem can be solved in polynomial time in any undirected graph However for directed graphs the problem remains di cult even for k This was shown b...

Based on the measurements of (D+ s ,D +) → f0(1370)π we determine, in a model independent way, the allowed ss̄ content in the scalar meson f0(1370). We find that, on the one hand, if this isoscalar resonance is a pure nn̄ state [nn̄ ≡ (uū + dd̄)/ √ 2 ], a very large W -annihilation term will be needed to accommodate D+ s → f0(1370)π. On the other hand, the ss̄ component of f0(1370) should be small e...

the purpose of this study was to assess exposure to hand-arm vibration in tiller users, forty users of tiller in northeastern provinces of iran were examined to measure hand-arm vibration parameters such as root mean square acceleration (rms), total equivalent acceleration, vibration dose value (vdv) and crest factor in three directions (x, y, and z) and various operating modes for comparing th...

Let (A; ') be the reduced free product of innnitely many C {algebras (A ; ') with respect to faithful states. Assume that the A are not too small, in a speciic sense. If ' is a trace then the positive cone of K 0 (A) is determined entirely by K 0 ('). If, furthermore, the image of K 0 (') is dense in R, then A has real rank zero. On the other hand, if ' is not a trace then A is simple and purel...

The objective of this article is to study the problem of generating implications with negation when only a set of purely positive implications related to a formal context K = (G,M, I) is provided. To that end, we define a sound and complete inference system which includes a characterization of implications whose left-hand side is a key in the context K|K̃ representing the apposition of the conte...

In this paper we explore the arithmetic correspondence between, on the one hand, (isogeny classes of) elliptic curves E defined over an imaginary quadratic field K of class number one, and on the other hand, rational newforms F of weight two for the congruence subgroups r0(n), where n is an ideal in the ring of integers R of K . This continues work of the first author and forms part of the Ph.D...

A p-page embedding of G is a vertex-ordering π of V (G) (along the “spine” of a book) and an assignment of edges to p half-planes (called “pages”) such that no page contains crossing edges. The pagenumber of G is the least p such that G has a p-page embedding. We disprove a conjecture of Ganley and Heath by showing that for all k ≥ 3, there are k-trees that do not embed in k pages. On the other...

The thermal stability of free pure C60-, as well as C60-alkali, and -alkaline-earth metal compound clusters is investigated. We find that small (C60)m-clusters (m<or=6) decay at comparatively low temperatures below 400 K, as a consequence of weak intermolecular van der Waals interaction. Adding barium or potassium to the clusters dramatically increases the decay temperatures for "magic" configu...

Information retrieval from textual data focuses on the construction of vocabularies that contain weighted term tuples. Such vocabularies can then be exploited by various text analysis algorithms to extract new knowledge, e.g., top-k keywords, top-k documents, etc. Topk keywords are casually used for various purposes, are often computed on-the-fly, and thus must be efficiently computed. To compa...

Pain or numbness in the neck, upper extremity, low back and/or leg is not infrequently caused by non-spinal conditions, which may be misdiagnosed as a wide variety of diseases: myelopathy, radiculopathy, discopathy, spondyloarthropathy or entrapment neuropathy. K Point syndrome is a symptom combination characterized by positive tenderness at K Point, which is located at the cranial musculotendi...