The Entropy formula for lexical richness is
The probability p-ith is calculated by dividing V-ith by N, where N is the total number of tokens in the text and V is the number of types. However, I can't seem to grasp the concept of V-ith? Any clarification would be greatly appreciated.
Source: Dale, Moisl, and Somers (p.551). "Handbook of Natural Language Processing" (2000).