preliminary vs simplex

preliminary

adj
  • In preparation for the main matter; initial, introductory, preparatory. 

noun
  • Any of a series of sports events that determine the finalists 

  • A preparation for a main matter; an introduction. 

  • A relatively minor contest that precedes a major one, especially in boxing 

simplex

adj
  • Single, simple; not complex. 

  • Unidirectional. 

noun
  • A monomorphemic word, one without affixes. 

  • An analogue in a space of arbitrary dimensionality of the triangle or tetrahedron; the convex hull of n+1 linearly independent points in n-dimensional space; in other words, the triangle, tetrahedron etc., generalized to an arbitrary number of dimensions. 

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