A 1.5 approximation algorithm for embedding hyperedges in a cycle

The problem of minimum congestion hypergraph embedding in a cycle (MCHEC) is to embed the hyperedges of a hypergraph as adjacent paths around a cycle, such that the maximum congestion over any physical link in the cycle is minimized. The problem is NP-complete in general, but solvable in polynomial time when all hyperedges contain exactly two vertices. In this paper, we first formulate the problem as an integer linear program (ILP). Then, a solution with approximation bound of 1.5(opt + 1) is presented by using a clockwise (2/3)-rounding algorithm, where opt denotes the optimal value of maximum congestion. To our knowledge, this is the best approximation bound known for the MCHEC problem.