Примеры использования Directed graphs на Английском языке и их переводы на Русский язык
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For directed graphs the same definitions apply.
Bellman-Ford algorithm[4][5][6] for directed graphs with arbitrary weights.
Among directed graphs, it is much easier to find incomparable pairs.
There are variants of modular decomposition for undirected graphs and directed graphs.
In directed graphs, the maximum spanning tree solution cannot be used.
Analogous definitions of hypohamiltonicity and hypotraceability for directed graphs have been considered by several authors.
Directed graphs are structures with a single binary relation(adjacency) on the domain the vertex set.
In the case of unweighted but directed graphs, strong inapproximability results are known.
A modified model for the descri ption of relational databases designed in the form of directed graphs has been suggested.
The cycle rank is an invariant of directed graphs that measures the level of nesting of cycles in the graph. .
Pavan, Tewari& Vinodchandran(2012)used book embedding to study the computational complexity theory of the reachability problem in directed graphs.
However, reachability for three-page directed graphs requires the full power of nondeterministic logarithmic space.
This package consists of a compiler, a class library, the language specification andprogramming manual, and a browser for displaying sources and directed graphs of class inheritance.(doc).
There is also a category with directed graphs as objects and homomorphisms as arrows, which is again a cartesian closed category.
The fact that homomorphisms can be composed leads to rich algebraic structures: a preorder on graphs, a distributive lattice, anda category one for undirected graphs and one for directed graphs.
The order→ for directed graphs is again a distributive lattice and a Heyting algebra, with join and meet operations defined as before.
In combinatorics, an area of mathematics, graph enumeration describes a class of combinatorial enumeration problems in which one must count undirected or directed graphs of certain types, typically as a function of the number of vertices of the graph. .
For directed graphs, one considers the singular values of the adjacency matrix A, which are equal to the roots of the eigenvalues of the symmetric matrix ATA.
Stated precisely, in any graph G its maximal pseudoforests consist of every tree component of G, together with one ormore disjoint 1-trees covering the remaining vertices of G. Versions of these definitions are also used for directed graphs.
It turns out that H-coloring problems for directed graphs are just as general and as diverse as CSPs with any other kinds of constraints.
Formally, let G(V, E) be any graph, and let S⊂ V be any subset of vertices of G. Then the induced subgraph G is the graph whose vertex set is S andwhose edge set consists of all of the edges in E that have both endpoints in S. The same definition works for undirected graphs, directed graphs, and even multigraphs.
For directed graphs, the situation is more complicated and in fact equivalent to the much more general question of characterizing the complexity of constraint satisfaction problems.
More generally, the reinterpretation the adjacency matrices of directed graphs as biadjacency matrices provides a combinatorial equivalence between directed graphs and balanced bipartite graphs. .
Theorem(Feder, Vardi 1998): For every constraint language Γ, the problem CSP(Γ) is equivalent under polynomial-time reductions to some H-coloring problem, for some directed graph H. Intuitively, this means that every algorithmic technique orcomplexity result that applies to H-coloring problems for directed graphs H applies just as well to general CSPs.
As they have observed,reachability for two-page directed graphs may be solved in unambiguous logarithmic space the analogue, for logarithmic space complexity, of the class UP of unambiguous polynomial-time problems.
The category of all directed graphs is thus nothing but the functor category SetC, where C is the category with two objects connected by two parallel morphisms(source and target), and Set denotes the category of sets.
The all-pairs shortest paths problem for unweighted directed graphs was introduced by Shimbel(1953), who observed that it could be solved by a linear number of matrix multiplications that takes a total time of OV4.
Another problem for directed graphs related to the circuit rank is the minimum feedback arc set, the smallest set of edges whose removal breaks all directed cycles.
There exist n-vertex Hamiltonian directed graphs with n(n+ 1)/2- 3 edges that are not pancyclic, but every Hamiltonian directed graph with at least n(n+ 1)/2- 1 edges is pancyclic.