Zipf's law

Zipf's law is an empirical law stating that the value of the n-th entry in a list of measured values is approximately inversely proportional to n. This law is commonly applied to the frequency table of words in a text or corpus of natural language, where the most common word occurs approximately twice as often as the next common one, and so on. It is often used in the form of the Zipf-Mandelbrot law, which takes the following form: frequency ∝ 1/(rank + b)^a, where a and b are fitted parameters. The law was discovered by George Kingsley Zipf in 1932, but was first observed by other researchers before him, including Felix Auerbach and Jean-Baptiste Estoup. It has since been found to apply to many other types of data studied in the physical and social sciences, and has been formalized as the Zipfian distribution.learn more on wikipedia