On 3-pushdown graphs with large separators
نویسندگان
چکیده
منابع مشابه
On 3-pushdown graphs with large separators
For an integer s let ZS(n), the s-iterated logarithm function, be defined inductively: [O(n) = n, [8+1(n) = log2(l8(n)) for s 2:: o. We show that for every fixed s and all n large enough, there is an n-vertex 3-pushdown graph whose smallest separator contains at least n(n/[8(n)) vertices.
متن کاملHypergraph Partitioning through Vertex Separators on Graphs
The modeling flexibility provided by hypergraphs has drawn a lot of interest from the combinatorial scientific community, leading to novel models and algorithms, their applications, and development of associated tools. Hypergraphs are now a standard tool in combinatorial scientific computing. The modeling flexibility of hypergraphs however, comes at a cost: algorithms on hypergraphs are inheren...
متن کاملString graphs and separators
String graphs, that is, intersection graphs of curves in the plane, have been studied since the 1960s. We provide an expository presentation of several results, including very recent ones: some string graphs require an exponential number of crossings in every string representation; exponential number is always sufficient; string graphs have small separators; and the current best bound on the cr...
متن کاملOn classes of graphs with strongly sublinear separators
For real numbers c, ε > 0, let Gc,ε denote the class of graphs G such that each subgraph H of G has a balanced separator of order at most c|V (H)|1−ε. A class G of graphs has strongly sublinear separators if G ⊆ Gc,ε for some c, ε > 0. We investigate properties of such graph classes, leading in particular to an approximate algorithm to determine membership in Gc,ε: there exist c > 0 such that f...
متن کاملGraphs with complete minimal k-vertex separators
G. A. Dirac characterized chordal graphs as those in which minimal vertex separators always induce complete subgraphs. I generalize a traditional (2-)vertex separator to a k-vertex separator — meaning a set S of vertices whose removal puts k independent vertices into k separate components. Generalizing Dirac’s theorem, the {P5, 2P3}-free chordal graphs are the graphs in which minimal k-separato...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Combinatorica
سال: 1989
ISSN: 0209-9683,1439-6912
DOI: 10.1007/bf02122679