The Wonderful Theory of Six Degrees of Separation (Part III) —— Ubiquitous Mathematical Expectation | Hip Pop Pandemonium

Among six billion people, if you randomly pick one person and try to find a connection with yourself, the number of intermediaries could be any number from 1 to 6 billion. The phrases "randomly pick one" and "random result" both imply that the essence of the six degrees of separation theory is also a matter that embodies the "unity of contradiction between chance and necessity."

The six degrees of separation theory is not used to precisely calculate the degree of connection between two specific individuals, but rather attempts to find the average of the 1.7999999997×10¹⁹ connection results generated by pairing all six billion people in the world. Since the term "average" is mentioned, this problem can be studied using the method of mathematical expectation in probability theory, because mathematical expectation is an advanced version of the average!

If we start from the perspective of probability theory, then the question of the six degrees of separation should be described as:

What is the mathematical expectation of the degree to which any two individuals in the world can be connected through a finite number of intermediaries?