Little Planet

Hello everyone, today I bring you the research of several scientists that interested me a lot.

The theory of "small worlds" or "small world" originated in the field of sociology and psychology, but has been applied and developed in various disciplines, including network science, computer science, biology and physics. The central idea behind the small world concept is that in complex networks, such as social networks, it is possible for any pair of nodes (individuals) to be connected by a relatively small number of intermediate steps.

Here are some key aspects related to small world theory:

Six degrees of separation:

The popular notion of "six degrees of separation" suggests that any person on Earth can be connected to any other person through a chain of acquaintances no longer than six intermediaries.
Small world model:

Hungarian mathematician Paul Erdős and Austrian-American mathematician Alfred Rényi introduced the concept of small world model in 1960. In this model, most nodes are connected to a small number of near neighbors, but there are also some links to nodes distant.
"Clustering" phenomenon:

Despite the short average distance between nodes, small-world networks often exhibit local clustering, meaning that nodes tend to form groups or "clusters" where they are strongly interconnected with each other.
Applications in social and technological networks:

The small world concept has been used to understand the structure of social networks, such as friendships on online platforms, as well as information networks on the Internet.
Small-world network models in biology and physics:

Small world theory has also been applied in biology to understand connectivity in neural networks and in physics to describe interactions in certain physical systems.
Milgram's experiment:

Psychologist Stanley Milgram conducted a famous experiment in the 1960s to investigate the six degrees of separation hypothesis. Participants were required to send letters to specific people using only known intermediaries. The results supported the idea that people were connected by relatively short social networks.
Small world theory has proven to be a powerful framework for understanding connectivity in diverse complex networks, and its applications continue to expand as new areas of research are explored.