Interval graphs play important roles in analysis of DNA chains in Benzer [S. Benzer, On the topology of the genetic fine structure, Proceedings of the National Academy of Sciences of the United States of America 45 (1959) 1607–1620], restriction maps of DNA in Waterman and Griggs [M.S. Waterman, J.R. Griggs, Interval graphs and maps of DNA, Bulletin of Mathematical Biology 48 (2) (1986) 189–195] and other related areas. In this paper, we study a new combinatorial opti
mization problem, named the
minimum clique partition problem with constrained bounds, in weighted interval graphs. For a weighted interval graph
G and a bound
B, partition the weighted intervals of this graph
G into the smallest number of cliques, such that each clique, consisting of some intervals whose intersection on a real line is not empty, has its weight not beyond
B. We obtain the following results: (1) this problem is
miImageURL/B6V1G-4NKXWR9-1-3/0?wchp=dGLbVtb-zSkWW" alt="Click to view the MathML source" align="absbottom" border="0" height=9 width=21>-hard in a strong sense, and it cannot be approximated within a factor
miImageURL/B6V1G-4NKXWR9-1-4/0?wchp=dGLbVtb-zSkWW" alt="Click to view the MathML source" align="absbottom" border="0" height=17 width=32> in polyno
mial time for any
ε>0; (2) we design three approximation algorithms with different constant factors for this problem; (3) for the version where all intervals have the same weights, we design an optimal algorithm to solve the problem in linear time.