Planar straight-line point-set embedding of trees with partial embeddings

Given a set P of n points in the plane, an n-node tree T, and a partial embedding E of T on P (i.e. a planar straight-line point-set embedding of some sub-trees of T on a sub-set of P), we show that the problem of deciding whether there is a planar straight-line point-set embedding of T on P that includes E is NP-complete. This problem was posed as an open problem in E. Di Giacomo et al. (2009) [8].