منابع مشابه
Colored Homomorphisms of Colored Mixed Graphs
The homomorphisms of oriented or undirected graphs, the oriented chromatic number, the relationship between acyclic coloring number and oriented chromatic number, have been recently studied. Improving and combining earlier techniques of N. Alon and T. H. Marshall (1998, J. Algebraic Combin. 8, 5 13) and A. Raspaud and E. Sopena (1994, Inform. Process. Lett. 51, 171 174) we prove here a general ...
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Evanescent wave spectroscopy using thin optically transparent electrodes and multiple reflections allows unique observations of the electrochemical interphase since the region of solution sampled is typically 100 nm from the electrode in the visible spectral region. This technique is found to be highly sensitive to the presence of absorbing adsorbed species
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The study of problems modeled by edge-colored graphs has given rise to important developments during the last few decades. For instance, the investigation of spanning trees for graphs provide important and interesting results both from a mathematical and an algorithmic point of view (see for instance [1]). From the point of view of applicability, problems arising in molecular biology are often ...
متن کاملMaximum colored trees in edge-colored graphs
Abstract We consider maximum properly edge-colored trees in edge-colored graphs Gc. We also consider the problem where, given a vertex r, determine whether the graph has a spanning tree rooted at r, such that all root-to-leaf paths are properly colored. We consider these problems from graphtheoretic as well as algorithmic viewpoints. We prove their optimization versions to be NP-hard in general...
متن کامل06 Drawing Colored Graphs on Colored Points
Let G be a planar graph with n vertices whose vertex set is partitioned into subsets V0, . . . , Vk−1 for some positive integer 1 ≤ k ≤ n and let S be a set of n distinct points in the plane partitioned into subsets S0, . . . , Sk−1 with |Vi| = |Si| (0 ≤ i ≤ k − 1). This paper studies the problem of computing a crossing-free drawing of G such that each vertex of Vi is mapped to a distinct point...
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ژورنال
عنوان ژورنال: American Journal of Science
سال: 1862
ISSN: 0002-9599
DOI: 10.2475/ajs.s2-33.98.229