Results 1 to 10 of about 7,289 (126)
On the Complexity of Digraph Colourings and Vertex Arboricity [PDF]
Discrete Mathematics & Theoretical Computer Science, 2020 It has been shown by Bokal et al. that deciding 2-colourability of digraphs is an NP-complete problem. This result was later on extended by Feder et al. to prove that deciding whether a digraph has a circular $p$-colouring is NP-complete for all rational
Winfried Hochstättler +2 more
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New Bounds for the Dichromatic Number of a Digraph [PDF]
Discrete Mathematics & Theoretical Computer Science, 2019 The chromatic number of a graph $G$, denoted by $\chi(G)$, is the minimum $k$ such that $G$ admits a $k$-coloring of its vertex set in such a way that each color class is an independent set (a set of pairwise non-adjacent vertices).
Narda Cordero-Michel +1 more
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Advancements and limitations of image-enhanced endoscopy in colorectal lesion diagnosis and treatment selection: A narrative review. [PDF]
DEN OpenAbstract Colorectal cancer (CRC) is a leading cause of cancer‐related mortality, highlighting the need for early detection and accurate lesion characterization. Traditional white‐light imaging has limitations in detecting lesions, particularly those with flat morphology or minimal color contrast with the surrounding mucosa.
Sakamoto T +3 more
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Perception and communication of relevant colours in paintings by observers with colour vision deficiencies [PDF]
Scientific ReportsIn a previous work, we empirically analysed the so-called “relevant colours” in paintings. These relevant colours describe the number of colours that stand out for an observer when glancing at a painting.
Juan Luis Nieves +3 more
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Enhancing strawberry resilience to saline, alkaline, and combined stresses with light spectra: impacts on growth, enzymatic activity, nutrient uptake, and osmotic regulation [PDF]
BMC Plant BiologyBackground This study examines the effects of various complementary light spectra on the growth, development, antioxidant activity, and nutrient absorption in strawberry plants under stress conditions.
Mohammad Reza Malekzadeh +2 more
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A Note on Graphs of Dichromatic Number 2 [PDF]
Discrete Mathematics & Theoretical Computer Science, 2021 Neumann-Lara and Škrekovski conjectured that every planar digraph is 2-colourable. We show that this conjecture is equivalent to the more general statement that all oriented K_5-minor-free graphs are 2-colourable.
Raphael Steiner
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Discussiones Mathematicae Graph Theory, 2022 We introduce a new notion of circular colourings for digraphs. The idea of this quantity, called star dichromatic number χ→*\vec \chi * (D) of a digraph D, is to allow a finer subdivision of digraphs with the same dichromatic number into such which are ...
Hochstättler Winfried, Steiner Raphael
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Cold-atom optical filtering enhanced by optical pumping
Frontiers in Physics, 2022 Atomic optical filters such as Faraday anomalous dispersion optical filters (FADOFs) or similar technologies can achieve very narrow optical bandwidth close to the scale of atomic linewidth, which can be greatly reduced in cold atoms. However, limited by
Xiaolei Guan +7 more
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Game-Perfect Semiorientations of Forests
Discussiones Mathematicae Graph Theory, 2022 We consider digraph colouring games where two players, Alice and Bob, alternately colour vertices of a given digraph D with a colour from a given colour set in a feasible way. The game ends when such move is not possible any more.
Andres Stephan Dominique +2 more
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Diversity of color vision: not all Australian marsupials are trichromatic. [PDF]
PLoS ONE, 2010 Color vision in marsupials has recently emerged as a particularly interesting case among mammals. It appears that there are both dichromats and trichromats among closely related species.
Wiebke Ebeling +2 more
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