divergence vs straightforwardness

divergence

noun
  • The process in which two or more populations accumulate genetic changes (mutations) through time. 

  • the operator which maps a function F=(F₁, ... Fₙ) from a n-dimensional vector space to itself to the function ∑ᵢ₌₁ⁿ(∂F_i)/(∂x_i) 

  • The degree to which two or more things diverge. 

straightforwardness

noun
  • The state or quality of being straightforward. 

How often have the words divergence and straightforwardness occurred in a corpus of books? (source: Google Ngram Viewer )