Six terminals located in different buildings need to be connected. The cost of connecting two terminals is proportional to the distance between them. Determine the connections to install to minimize the total cost.

Further explanation of this example: 'Applications of optimization with Xpress-MP', Section 12.4 'Construction of a cabled network' (g4cable.mos)

! Data file for `spanningtree.mos'

DIST: [   0 120  92 265 149 194
        120   0 141 170  93 164
         92 141   0 218 103 116
        265 170 218   0 110 126
        149  93 103 110   0  72
        194 164 116 126  72   0]

POS: [[18 62] [32 29] [44 65] [78 19] [57 40] [78 53]]