Improved approximability and non-approximability results for graph diameter decreasing problems
نویسندگان
چکیده
منابع مشابه
Non-approximability results for scheduling
We provide several non-approximability results for deterministic scheduling problems whose objective is to minimize the total job completion time. Unless P = NP, none of the problems under consideration can be approximated in polynomial time within arbitrarily good precision. Most of our results are derived by APX-hardness proofs. We show that, whereas scheduling on unrelated machines with unit...
متن کاملImproved Non-approximability Results for Vertex Cover with Density Constraints
We provide new non-approximability results for the restrictions of the Min Vertex Cover problem to bounded-degree, sparse and dense graphs. We show that, for a suuciently large B, the recent 16/15 lower bound proved by Bellare et al. 3] extends with negligible loss to graphs with bounded degree B. Then, we consider sparse graphs with no dense components (i.e. everywhere sparse graphs), and we s...
متن کاملNon-approximability Results for Scheduling Problems with Minsum Criteria
We provide several non-approximability results for deterministic scheduling problems whose objective is to minimize the total job completion time. Unless P = NP, none of the problems under consideration can be approximated in polynomial time within arbitrarily good precision. Most of our results are derived by Max SNP hardness proofs. Among the investigated problems are: scheduling unrelated ma...
متن کامل(In)approximability Results for Pattern Matching Problems
We consider the approximability of three recently introduced pattern matching problems which have been shown to be NP-hard. Given two strings as input, the first problem is to find the longest common parameterised subsequence between two strings. The second is a maximisation variant of generalised function matching and the third is a a maximisation variant of generalised parameterised matching....
متن کاملDual parameterization and parameterized approximability of subset graph problems
We discuss approximability in FPT-time for the class of subset optimization graph problems where a feasible solution S is a subset of the vertex set of the input graph. This class encompasses many well-known problems, such as min dominating set, min vertex cover, max independent set, min feedback vertex set. We study approximability of such problems with respect to the dual parameter n − k wher...
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: Theoretical Computer Science
سال: 2012
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2011.05.014