“…On one side, Nelson's derivation is based on a variational principle, which makes his approach more attractive. However, although different formulations of the NLS on graphs have been introduced in physics and mathematics [8,11,15,16,29], not much is known through Nelson's approach, mainly because the theory of discrete optimal transport has not been seriously explored until the past few years [12,24,26]. On the other side, most of the discrete formulations for the NLS, especially those defined on lattices, are obtained by discretizations of the continuous NLS.…”