at this stageajodanzaand bordo are in category colina and erizo are in category and flor is in category as shown in figure as we work our way through the algorithmtowns move from category to and from to bordo colina ajo flor danza towns with offices (vertices in the treefigure erizo fringe towns (not in the treeunknown towns (not in the treepartway through the minimum spanning tree algorithm building the bordo-erizo link at this pointajodanzaand bordo are connected to the cable system and have offices you already know the costs from ajo and danza to towns in category but you don' know these costs from bordo so from bordo you send out surveyors to colina and erizo they report back costs of million dollars to colina and to erizo here' the new listbordo-erizo$ million danza-colina$ million bordo-colina$ million danza-erizo$ million the danza-bordo link was on the previous list but is not on this one becauseas we notedthere' no point in considering links to towns that are already connectedeven by an indirect route from this list we can see that the cheapest route is bordo-erizoat million dollars you send out the crew to install this cable linkand you build an office in erizo (see figure