5 research outputs found
Connecting Terminals and 2-Disjoint Connected Subgraphs
Given a graph and a set of terminal vertices we say that a
superset of is -connecting if induces a connected graph, and
is minimal if no strict subset of is -connecting. In this paper we prove
that there are at most minimal -connecting sets when and that
these can be enumerated within a polynomial factor of this bound. This
generalizes the algorithm for enumerating all induced paths between a pair of
vertices, corresponding to the case . We apply our enumeration algorithm
to solve the {\sc 2-Disjoint Connected Subgraphs} problem in time
, improving on the recent algorithm of Cygan et
al. 2012 LATIN paper.Comment: 13 pages, 1 figur
Two-sets cut-uncut on planar graphs
We study the following Two-Sets Cut-Uncut problem on planar graphs. Therein,
one is given an undirected planar graph and two sets of vertices and
. The question is, what is the minimum number of edges to remove from ,
such that we separate all of from all of , while maintaining that every
vertex in , and respectively in , stays in the same connected component.
We show that this problem can be solved in time with a
one-sided error randomized algorithm. Our algorithm implies a polynomial-time
algorithm for the network diversion problem on planar graphs, which resolves an
open question from the literature. More generally, we show that Two-Sets
Cut-Uncut remains fixed-parameter tractable even when parameterized by the
number of faces in the plane graph covering the terminals , by
providing an algorithm of running time .Comment: 22 pages, 5 figure
Connecting Terminals and 2-Disjoint Connected Subgraphs
Abstract. Given a graph G = (V, E) and a set of terminal vertices T we say that a superset S of T is T -connecting if S induces a connected graph, and S is minimal if no strict subset of S is T -connecting. In this paper we prove that there are at most minimal T -connecting sets when |T | ≤ n/3 and that these can be enumerated within a polynomial factor of this bound. This generalizes the algorithm for enumerating all induced paths between a pair of vertices, corresponding to the case |T | = 2. We apply our enumeration algorithm to solve the 2-Disjoint Connected Subgraphs problem in time O * (1.7804 n ), improving on the recent O * (1.933 n ) algorithm of Cygan et al. 2012 LATIN paper