corollary vs sequel

corollary

noun
  • A proposition which follows easily from the proof of another proposition. 

  • A gift beyond what is actually due; an addition or superfluity. 

  • An a fortiori occurrence, as a result of another effort without significant additional effort. 

adj
  • Occurring as a natural consequence or result; attendant; consequential. 

  • Forming a proposition that follows from one already proved. 

sequel

noun
  • The remainder of the text; what follows. Used exclusively in the set phrase "in the sequel". 

  • A narrative that is written after another narrative set in the same universe, especially a narrative that is chronologically set after its predecessors, or (perhaps improper usage) any narrative that has a preceding narrative of its own. 

  • Thirlage. 

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