Graphs with small bandwidth and cutwidth
نویسندگان
چکیده
We give counter-examples to the following conjecture which arose in the study of small bandwidth graphs. “For a graph G, suppose that IV(G’)( < 1 + ci . diameter (G’) for any connected subgraph G’ of G, and that G does not contain any refinement of the complete binary tree of cz levels. Is it true that the bandwidth of G can be bounded above by a constant c depending only on c, and c,?” On the other hand, we show that if the maximum degree of G is bounded and G does not contain any refinement of a complete binary tree of a specified size, then the cutwidth and the topological bandwidth of G are also bounded.
منابع مشابه
On Bandwidth, Cutwidth, and Quotient Graphs
The bandwidth and the cutwidth are fundamental parameters which can give indications on the complexity of many problems described in terms of graphs. In this paper, we present a method for nding general upper bounds for the bandwidth and the cutwidth of a given graph from those of any of its quotient graphs. Moreover, general lower bounds are obtained by using vertex-and edge-bisection notions....
متن کاملComputing the Cutwidth of Bipartite Permutation Graphs in Linear Time
The problem of determining the cutwidth of a graph is a notoriously hard problem which remains NP-complete under severe restrictions on input graphs. Until recently, nontrivial polynomial-time cutwidth algorithms were known only for subclasses of graphs of bounded treewidth. Very recently, Heggernes et al. (SIAM J. Discrete Math., 25 (2011), pp. 1418–1437) initiated the study of cutwidth on gra...
متن کاملCutwidth of Split Graphs and Threshold Graphs
We give a linear-time algorithm to compute the cutwidth of threshold graphs, thereby resolving the computational complexity of cutwidth on this graph class. Threshold graphs are a well-studied subclass of interval graphs and of split graphs, both of which are unrelated subclasses of chordal graphs. To complement our result, we show that cutwidth is NPcomplete on split graphs, and consequently a...
متن کاملCutwidth of Split Graphs, Threshold Graphs, and Proper Interval Graphs
We give a linear-time algorithm to compute the cutwidth of threshold graphs, thereby resolving the computational complexity of cutwidth on this graph class. Although our algorithm is simple and intuitive, its correctness proof relies on a series of non-trivial structural results, and turns out to be surprisingly complex. Threshold graphs are a well-studied subclass of interval graphs and of spl...
متن کاملCutwidth and degeneracy of graphs
We prove an inequality involving the degeneracy, the cutwidth and the sparsity of graphs. It implies a quadratic lower bound on the cutwidth in terms of the degeneracy for all graphs and an improvement of it for clique-free graphs.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Discrete Mathematics
دوره 75 شماره
صفحات -
تاریخ انتشار 1989