Comments on the 'polynomial formulation and heuristic-based approach for the k-travelling repairman problem'

The paper 'polynomial formulation and heuristic-based approach for the k-travelling repairman problem' claims to present the first polynomial formulation for the k-travelling repairman problem (k-TRP). We first make some corrections on this formulation and we show that the first polynomial size formulation for k-TRP is the one proposed by Kara et al. (2008).