# Interacting Networks with Antagonistic Interactions

**When:**Thursday, December 06, 2012 at 1:30 pm

**Where:**DA 5th fl

**Speaker**: Ginestra Bianconi

**Organization**: Northeastern University

**Sponsor**: Joint Network Seminar

Many networks do not live in isolation but are strongly interacting, with profound consequences on their dynamics. The interaction between nodes of two interacting networks can be interdependent, or antagonistic. In presence of antagonistic interactions, the functionality, or activity, of a node in a network is incompatible with the functionality, of the linked node in the other interacting network

In the first part of the talk we will consider percolation in interacting networks with antagonistic interactions. Recently, new results on percolation of interdependent networks have shown that the percolation transition can be first order. Here we show that, when considering antagonistic interactions between interacting networks, the percolation process might present a bistability of the steady state solutions, with strong implications for the dynamics defined in these networks.

In the second part of the talk we will consider the case of two interacting antagonistic social networks and, in the context of a simple model, we address the case of political elections. Each network represents a competing party and every agent on the election day can choose to be either active in one of the two networks (vote for the corresponding party) or to be inactive in both (not vote). The opinion dynamics during the election campaign is described through a simulated annealing algorithm. We find that for a large region of the parameter space the result of the competition between the two parties allows for the existence of pluralism in the society, where both parties have a finite share of the votes. The central result is that a densely connected social network is key for the final victory of a party. However, small committed minorities can play a crucial role, and even reverse the election outcome.