 
Summary: Additive Approximation for EdgeDeletion Problems
Noga Alon
Asaf Shapira
Benny Sudakov
Abstract
A graph property is monotone if it is closed under removal of vertices and edges. In this
paper we consider the following algorithmic problem, called the edgedeletion problem; given a
monotone property P and a graph G, compute the smallest number of edge deletions that are
needed in order to turn G into a graph satisfying P. We denote this quantity by EP (G). The
first result of this paper states that the edgedeletion problem can be efficiently approximated for
any monotone property.
· For any fixed > 0 and any monotone property P, there is a deterministic algorithm, which
given a graph G = (V, E) of size n, approximates EP (G) in linear time O(V  + E) to
within an additive error of n2
.
Given the above, a natural question is for which monotone properties one can obtain better
additive approximations of EP . Our second main result essentially resolves this problem by giving
a precise characterization of the monotone graph properties for which such approximations exist.
1. If there is a bipartite graph that does not satisfy P, then there is a > 0 for which it is
possible to approximate EP to within an additive error of n2
