Results 1 to 10 of about 58,255 (219)
On minimal blocking sets of the generalized quadrangle $Q(4, q)$ [PDF]
Discrete Mathematics & Theoretical Computer Science, 2005 The generalized quadrangle $Q(4,q)$ arising from the parabolic quadric in $PG(4,q)$ always has an ovoid. It is not known whether a minimal blocking set of size smaller than $q^2 + q$ (which is not an ovoid) exists in $Q(4,q)$, $q$ odd. We present results
Miroslava Cimráková, Veerle Fack
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THE HARMONIOUS, ODD HARMONIOUS, AND EVEN HARMONIOUS LABELING
Barekeng, 2022 Suppose is a simple and connected graph with edges. A harmonious labeling on a graph is an injective function so that there exists a bijective function where for each An odd harmonious labeling on a graph is an injective function from to non ...
Ahmad Lasim +2 more
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Graphs of Morphisms of Graphs [PDF]
The Electronic Journal of Combinatorics, 2008 This is an account for the combinatorially minded reader of various categories of directed and undirected graphs, and their analogies with the category of sets. As an application, the endomorphisms of a graph are in this context not only composable, giving a monoid structure, but also have a notion of adjacency, so that the set of endomorphisms is both
Ronald Brown +3 more
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COVID-19 mortality in women and men in sub-Saharan Africa: a cross-sectional study
BMJ Global Health, 2021 Introduction Since sex-based biological and gender factors influence COVID-19 mortality, we wanted to investigate the difference in mortality rates between women and men in sub-Saharan Africa (SSA).Method We included 69 580 cases of COVID-19, stratified ...
Claire Somerville +15 more
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Hadamard matrices of order 36 and double-even self-dual [72,36,12] codes [PDF]
Discrete Mathematics & Theoretical Computer Science, 2005 Before this work, at least 762 inequivalent Hadamard matrices of order 36 were known. We found 7238 Hadamard matrices of order 36 and 522 inequivalent [72,36,12] double-even self-dual codes which are obtained from all 2-(35,17,8) designs with an ...
Iliya Bouyukliev +2 more
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On the enumeration of uniquely reducible double designs [PDF]
Discrete Mathematics & Theoretical Computer Science, 2005 A double $2$-$(v,k,2 \lambda)$ design is a design which is reducible into two $2$-$(v,k,\lambda)$ designs. It is called uniquely reducible if it has, up to equivalence, only one reduction.
Veerle Fack +2 more
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Planar Graphs as VPG-Graphs [PDF]
Journal of Graph Algorithms and Applications, 2013 Summary: A graph is \(B_k\)-VPG when it has an intersection representation by paths in a rectangular grid with at most \(k\) bends (turns). It is known that all planar graphs are \(B_3\)-VPG and this was conjectured to be tight. We disprove this conjecture by showing that all planar graphs are \(B_2\)-VPG.
Steven Chaplick, Torsten Ueckerdt
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Odd Harmonious Labeling of Pn ⊵ C4 and Pn ⊵ D2(C4)
Indonesian Journal of Combinatorics, 2021 A graph G with q edges is said to be odd harmonious if there exists an injection f:V(G) → ℤ2q so that the induced function f*:E(G)→ {1,3,...,2q-1} defined by f*(uv)=f(u)+f(v) is a bijection.Here we show that graphs constructed by edge comb product of ...
Sabrina Shena Sarasvati +2 more
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Embedding Graphs into Embedded Graphs [PDF]
Algorithmica, 2020 A (possibly denerate) drawing of a graph $G$ in the plane is approximable by an embedding if it can be turned into an embedding by an arbitrarily small perturbation. We show that testing, whether a straight-line drawing of a planar graph $G$ in the plane is approximable by an embedding, can be carried out in polynomial time, if a desired embedding of ...
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BMC Public Health, 2022 Emerging infectious diseases are a growing threat in sub-Saharan African countries, but the human and technical capacity to quickly respond to outbreaks remains limited.
Sara Botero-Mesa +47 more
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