Comments on the T-dual of the gravity dual of D5-branes on S3S^3

We consider an abelian T-duality on a deformation of the gravitational solution of \cite{Maldacena2001}, which is the gravity dual of $N_c$ D5-branes wrapping a three-cycle inside a manifold that admits a $G_2$ structure. Performing the T-duality we find $N_c$ D$4$-branes wrapping a two-cycle with non-trivial antisymmetric fields in the NS-NS and RR sector. We study some aspects of its dual field theory and we compare with the original solution.Comment: 26 page

Innovation Success and Structural Change: An Abstract Agent Based Study

A model is developed to study the effectiveness of innovation and its impact on structure creation and structure change on agent-based societies. The abstract model that is developed is easily adapted to any particular field. In any interacting environment, the agents receive something from the environment (the other agents) in exchange for their effort and pay the environment a certain amount of value for the fulfilling of their needs or for the very price of existence in that environment. This is coded by two bit strings and the dynamics of the exchange is based on the matching of these strings to those of the other agents. Innovation is related to the adaptation by the agents of their bit strings to improve some utility function.Comment: 20 pages, 12 figure

Non-Abelian T-duality for nonrelativistic holographic duals

We find new type II backgrounds with non-relativistic symmetries via non-Abelian T-duality. First we consider geometries with Galilean symmetries in type IIA, which have been identified as non-relativistic generalizations of the ABJM background and massive IIA supergravities. We then consider the non-Abelian T-duality transformation on the backgrounds with Lifshitz symmetry constructed by Donos and Gauntlett. Using gauge/gravity duality we study aspects of the field theory dual to these backgrounds.Comment: 43 pages, 4 figures; typos and one eq. corrected, references adde

Function and form in networks of interacting agents

The main problem we address in this paper is whether function determines form when a society of agents organizes itself for some purpose or whether the organizing method is more important than the functionality in determining the structure of the ensemble. As an example, we use a neural network that learns the same function by two different learning methods. For sufficiently large networks, very different structures may indeed be obtained for the same functionality. Clustering, characteristic path length and hierarchy are structural differences, which in turn have implications on the robustness and adaptability of the networks. In networks, as opposed to simple graphs, the connections between the agents are not necessarily symmetric and may have positive or negative signs. New characteristic coefficients are introduced to characterize this richer connectivity structure.Comment: 27 pages Latex, 11 figure