Colouring the cortex
نویسندگان
چکیده
منابع مشابه
Colouring graphs with bounded generalized colouring number
Given a graph G and a positive integer p, χp(G) is the minimum number of colours needed to colour the vertices of G so that for any i ≤ p, any subgraph H of G of tree-depth i gets at least i colours. This paper proves an upper bound for χp(G) in terms of the k-colouring number colk(G) of G for k = 2p−2. Conversely, for each integer k, we also prove an upper bound for colk(G) in terms of χk+2(G)...
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A graph G is chordless if no cycle in G has a chord. In the present work we investigate the chromatic index and total chromatic number of chordless graphs. We describe a known decomposition result for chordless graphs and use it to establish that every chordless graph of maximum degree ∆ ≥ 3 has chromatic index ∆ and total chromatic number ∆+1. The proofs are algorithmic in the sense that we ac...
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It was proved by Tutte in [23] that for every finite n an n -chromatic triangle-free graph exists. Later Erdos and Rado [10] extended this result to infinite n. Another extension of a different kind was found by Erdos in [5]: if n, s are finite numbers, there exists an n-chromatic graph without circuits of length at most s. The proof was non-constructive, a construction was later found by Lov£s...
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Current digital camera sensors are inherently sensitive to the near-infrared part of the spectrum. To prevent the near-IR contamination of images, an IR blocking filter (hot mirror) is placed in front of the sensor. In this work, we start by replacing the camera’s hot mirror by a piece of clear glass, thus making the camera sensitive to both visible and near-IR light. Using a pair of lens-mount...
متن کاملCircular Colouring the Plane
The unit distance graph R is the graph with vertex set R2 in which two vertices (points in the plane) are adjacent if and only if they are at Euclidean distance 1. We prove that the circular chromatic number of R is at least 4, thus “tightening” the known lower bound on the chromatic number of R.
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ژورنال
عنوان ژورنال: Nature
سال: 1997
ISSN: 0028-0836,1476-4687
DOI: 10.1038/40275