In this paper we show that the problem to decide whether the hamiltonian index of a given graph is less or equal to a given constant is ∗ Research supported by grants No. 1M0545 and MSM 4977751301 of the Czech Ministry of Education. † Supported by Nature Science Funds of China under Contract Grant No.: 10671014 1
Zdenek Ryjácek, Gerhard J. Woeginger, Limin