Example

-- IntSet \not<= FatSet
  • FatSet -- insert, select, size
  • IntSet -- insert, delete, select, size

History property

-- not satisfied by IntSet
  • \A s : FatSet. \A %f, %q : State. %f < %q /\ s \e dom (%q).
    \hspace{2cm} \A x : Int. x \e s_{%f} => x \e s_{%q}

slide: History properties -- example