Havlin addresses a broad spectrum of issues within the field. He and his team demonstrated, for example, that complex networks, such as epidemics or traffic networks, often follow mathematical patterns that repeat on different scales. He also developed the first approach to a theory that describes the behaviour of liquids, gases or electricity in materials with an unpredictable structure through the formation of connections, i.e. the 'percolation theory'.
Havlin's research makes clear how complex networks mutually influence each other. A concept often referred to as 'networks of networks'. It highlights, for example, how failures in one network can lead to a chain reaction of failures in other interconnected systems. This knowledge has significant implications for various aspects of our daily lives, such as the impact of a power failure on our internet and other communication systems.