The small-world property is known to have a profound effect on the navigation efficiency of complex networks [J. M. Kleinberg, Nature 406, 845 (2000)]. Accordingly, the proper addition of shortcuts to a regular substrate can lead to the formation of a highly efficient structure for information propagation. Here we show that enhanced flow properties can also be observed in these complex topologies. Precisely, our model is a network built from an underlying regular lattice over which long-range connections are randomly added according to the probability, Pij ∼ r −α ij , where rij is the Manhattan distance between nodes i and j, and the exponent α is a controlling parameter. The mean two-point global conductance of the system is computed by considering that each link has a local conductance given by gij ∝ r −δ ij , where δ determines the extent of the geographical limitations (costs) on the long-range connections. Our results show that the best flow conditions are obtained for δ = 0 with α = 0, while for δ ≫ 1 the overall conductance always increases with α. For δ ≈ 1, α = d becomes the optimal exponent, where d is the topological dimension of the substrate. Interestingly, this exponent is identical to the one obtained for optimal navigation in small-world networks using decentralized algorithms.The Laplacian matrix operator is a general description for systems presenting two essential properties: (i) they obey local conservation of some load, and (ii) [10,11], among others. In these problems, one is frequently interested in the stationary state, where currents in each edge of a given network can be determined using local conservation laws. In the field of complex networks, in particular, the Laplacian operator has been employed as a conceptual approach for determining the nature of the community structure in the networks [12], in the context of network synchronization [13], as well as to study network flow [14][15][16][17][18][19].Given a regular network as an underlying substrate, it has been shown that the addition of a small set of random long-range links can greatly reduce the shortest paths among its sites. In particular, if the average shortest path ℓ s grows slowly with the network size N , typically when ℓ s ∼ log(N ), the network is called a small world [20][21][22]. If one considers the effect of constraining the allocation of the long-range connections with a probability decaying with the distance, P ij ∼ r −α ij , results in an effective dimensionality for the chemical distances that depends on the value of α [23]. For the case in which the regular underlying lattice is one-dimensional, the small-world behavior has only been detected for α < 2, with ℓ s reaching a minimum at α opt = 0 [23]. The two-dimensional case was also investigated [24], yielding similar results.The situation is much more complex if one does not have the global information of all the short-cuts present in the network. As a consequence, the traveler does not have a priori knowledge of the shortest path. Optimal navigation with loca...