The cost of trust in the dynamics of best attachment

The need of trust is growing in several contexts as e-commerce, virtual communities, distributed on-line services and many others as an essential precautionary component for users during interactions with strangers, either other people or virtual agents. Generally trust metrics endorse the principle "the higher the trust, the more legitimate that user will be"; a consequence is that getting trusted must require some effort, otherwise all participants would easily achieve high trustworthiness. In this work we study how a user can achieve and preserve a good trust and what costs it requires over time; we also investigate some heuristics that allow reducing the complexity in exploring the rank-effort space especially for large networks.