partially ordered set vs succession

partially ordered set

noun
  • The ordered pair comprising a set and its partial order. 

  • A set that has a given, elsewhere specified partial order. 

succession

noun
  • A sequence of things in order. 

  • In Roman and Scots law, the taking of property by one person in place of another. 

  • An act of following in sequence. 

  • A group of rocks or strata that succeed one another in chronological order. 

  • A right to take possession. 

  • A race or series of descendants. 

  • A passing of royal powers. 

  • Rotation, as of crops. 

How often have the words partially ordered set and succession occurred in a corpus of books? (source: Google Ngram Viewer )