Results 41 to 50 of about 240,213 (310)
A determinacy approach to Borel combinatorics [PDF]
J. Amer. Math. Soc. 29 (2016), 579-600, 2013 We introduce a new method, involving infinite games and Borel determinacy, which we use to answer several well-known questions in Borel combinatorics.
arxiv +1 more source
Polyhedral Combinatorics of UPGMA Cones [PDF]
, 2012 Distance-based methods such as UPGMA (Unweighted Pair Group Method with Arithmetic Mean) continue to play a significant role in phylogenetic research. We use polyhedral combinatorics to analyze the natural subdivision of the positive orthant induced by ...
Davidson, Ruth, Sullivant, Seth
core +2 more sources
On the Combinatorics of Smoothing [PDF]
Journal of Mathematical Sciences, 2016 Many invariants of knots rely upon smoothing the knot at its crossings. To compute them, it is necessary to know how to count the number of connected components the knot diagram is broken into after the smoothing. In this paper, it is shown how to use a modification of a theorem of Zulli together with a modification of the spectral theory of graphs to ...
openaire +3 more sources
Combinatorics of Bricard’s octahedra [PDF]
Comptes Rendus. Mathématique, 2021 We re-prove the classification of flexible octahedra, obtained by Bricard at the beginning of the XX century, by means of combinatorial objects satisfying some elementary rules. The explanations of these rules rely on the use of a well-known creation of modern algebraic geometry, the moduli space of stable rational curves with marked points, for the ...
Gallet M +3 more
openaire +4 more sources
Skew Randi'c matrix and skew Randi'c energy [PDF]
Transactions on Combinatorics, 2016 Let $G$ be a simple graph with an orientation $sigma$, which assigns to each edge a direction so that $G^sigma$ becomes a directed graph. $G$ is said to be the underlying graph of the directed graph $G^sigma$.
Ran Gu, Fei Huang, Xueliang Li
doaj
Rainbow Vertex-Connection and Forbidden Subgraphs
Discussiones Mathematicae Graph Theory, 2018 A path in a vertex-colored graph is called vertex-rainbow if its internal vertices have pairwise distinct colors. A vertex-colored graph G is rainbow vertex-connected if for any two distinct vertices of G, there is a vertex-rainbow path connecting them ...
Li Wenjing, Li Xueliang, Zhang Jingshu
doaj +1 more source
List circular backbone colouring [PDF]
Discrete Mathematics & Theoretical Computer Science, 2014 A natural generalization of graph colouring involves taking colours from a metric space and insisting that the endpoints of an edge receive colours separated by a minimum distance dictated by properties of the edge.
Frederic Havet, Andrew D. King
doaj +1 more source
General Randic matrix and general Randi'c energy [PDF]
Transactions on Combinatorics, 2014 Let $G$ be a simple graph with vertex set $V(G) = {v_1, v_2,ldots , v_n}$ and $d_i$ the degree of its vertex $v_i$, $i = 1, 2, cdots, n$. Inspired by the Randi'c matrix and the general Randi'c index of a graph, we introduce the concept of general ...
Ran Gu;, Fei Huang, Xueliang Li
doaj
Erdős-Gallai-Type Results for Total Monochromatic Connection of Graphs
Discussiones Mathematicae Graph Theory, 2019 A graph is said to be total-colored if all the edges and the vertices of the graph are colored. A total-coloring of a graph is a total monochromatically-connecting coloring (TMC-coloring, for short) if any two vertices of the graph are connected by a ...
Jiang Hui, Li Xueliang, Zhang Yingying
doaj +1 more source
Ward identities and combinatorics of rainbow tensor models [PDF]
, 2017 A bstractWe discuss the notion of renormalization group (RG) completion of non-Gaussian Lagrangians and its treatment within the framework of Bogoliubov-Zimmermann theory in application to the matrix and tensor models.
H. Itoyama +3 more
semanticscholar +1 more source