Towards Distributivity in FCA for Phylogenetic Data

It is known that a distributive lattice is a median graph, and that a distributive ∨-semilattice can be thought of as a median graph iff every triple of elements such that the infimum of each couple of its elements exists, has an infimum. Since a lattice without its bottom element is obviously a ∨-semilattice, using the FCA formalism, we investigate the following problem: Given a semilattice L obtained from a lattice by deletion of the bottom element, is there a minimum distributive ∨-semilattice L d such that L can be order embedded into L d? We give a negative answer to this question by providing a counter-example.