Pienmaailmaverkkoisuus

Pienmaailmaverkkoisuus, sometimes translated as "small-worldness," describes a structural property found in many complex networks, including social networks, biological systems, and technological infrastructures. A network exhibits small-world properties if it is highly clustered, meaning that neighbors of a node are likely to be connected to each other, and simultaneously has a short average path length between any two nodes.

The concept was popularized by a 1998 paper by Duncan Watts and Steven Strogatz in the journal Nature. They studied networks formed by arranging nodes in a regular lattice and then randomly rewiring a small fraction of the connections. Their findings indicated that even a modest number of random connections could dramatically reduce the average path length while largely preserving the high clustering coefficient characteristic of the lattice.

This "six degrees of separation" phenomenon, where any two individuals in the world can be connected through a short chain of acquaintances, is a classic example of small-world networks. The implications of small-worldness are widespread, influencing the spread of information, diseases, and even the robustness of networks to failures. Understanding this property is crucial for designing and analyzing interconnected systems.