Overview
My research focuses on the mathematical analysis of signed networks — systems where interactions can be either positive or negative, such as alliances and conflicts in international relations, excitatory and inhibitory links in neural networks, or cooperative and competitive dynamics in ecology and economics. While network science has traditionally overlooked negative edges, I find them essential to understanding systems shaped by antagonism, inhibition, or polarization.
The core aim of my research is to develop robust mathematical tools to analyze the structure and dynamics of signed networks. This includes:
Defining and characterizing emergent features like local and global balance, effective enmities, and polarization.
Building theoretically-sounded algorithms to detect opposing factions, find central nodes, and reconstruct signed networks from noisy data.
Understand how the structure of signed networks affects dynamical processes taking place on them.
Applying the theoretical results to practical settings in geopolitics, social systems, finance, and biology.
This research led to several theoretical and applied advances:
I introduced walk-based measures of local balance and communicability that uncover hidden structure in signed networks, including effective alliances, antagonisms, and node-level polarization. Link
I developed distance and similarity metrics based on communicability that preserve negative information and allow standard data analysis tools (e.g., clustering, embedding) to be applied to signed data. Link
I applied these tools to historical datasets on international relations, showing how fluctuations in balance indices align with major geopolitical events and transitions, offering a quantitative complement to traditional historiography. Link
I also explored contagion dynamics in signed networks, and applied these models to understand the echo chamber effect in networks with hostile links. Link