Solving the Minimum Label Spanning Tree Problem by Mathematical Programming Techniques

Figure 10

Valid LP-solution of EC_tn with 𝑓^lp=2+𝜖(𝑙_𝑎=1,𝑙_𝑏=𝜖,𝑙_𝑐=1) that is not valid for SCF_tn. It can however be transformed to such, by increasing 𝑥_3,4 to 1/5, yielding 𝑓^lp=2+1/5. It is easy to see, that this solution is still not valid for DCut_tn.