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In the mathematical field of graph theory, a word-representable graph is a graph that can be characterized by a word (or sequence) whose entries alternate in a prescribed way. In particular, if the vertex set of the graph is V , one should be able to choose a word w over the alphabet V such that letters a and b alternate in w if and only if the ...
A universal graph is a graph that contains as subgraphs all graphs in a given family of graphs, or all graphs of a given size or order within a given family of graphs. 2. A universal vertex (also called an apex or dominating vertex) is a vertex that is adjacent to every other vertex in the graph.
A graph with three vertices and three edges. A graph (sometimes called an undirected graph to distinguish it from a directed graph, or a simple graph to distinguish it from a multigraph) [4] [5] is a pair G = (V, E), where V is a set whose elements are called vertices (singular: vertex), and E is a set of unordered pairs {,} of vertices, whose elements are called edges (sometimes links or lines).
Graph coloring [2] [3]: GT4 Graph homomorphism problem [3]: GT52 Graph partition into subgraphs of specific types (triangles, isomorphic subgraphs, Hamiltonian subgraphs, forests, perfect matchings) are known NP-complete. Partition into cliques is the same problem as coloring the complement of the given graph.
A graph structure can be extended by assigning a weight to each edge of the graph. Graphs with weights, or weighted graphs, are used to represent structures in which pairwise connections have some numerical values. For example, if a graph represents a road network, the weights could represent the length of each road.
When the prefix "re-" is added to a monosyllabic word, the word gains currency both as a noun and as a verb. Most of the pairs listed below are closely related: for example, "absent" as a noun meaning "missing", and as a verb meaning "to make oneself missing". There are also many cases in which homographs are of an entirely separate origin, or ...
A homograph (from the Greek: ὁμός, homós 'same' and γράφω, gráphō 'write') is a word that shares the same written form as another word but has a different meaning. [1] However, some dictionaries insist that the words must also be pronounced differently, [ 2 ] while the Oxford English Dictionary says that the words should also be of ...
A term graph is a representation of an expression in a formal language as a generalized graph whose vertices are terms [clarify]. [1] Term graphs are a more powerful form of representation than expression trees because they can represent not only common subexpressions (i.e. they can take the structure of a directed acyclic graph) but also cyclic/recursive subexpressions (cyclic digraphs).