Abstract inheritance

  • declarative relation among entities

Inheritance networks

  • isa-trees -- partial ordering
  • isa/is-not -- bipolar, is-not inference

Non-monotonic reasoning


    Nixon is-a Quaker
    Nixon is-a Republican
    Quakers are Pacifists
    Republicans are not Pacifists

Incremental system evolution is in practice non-monotonic!

slide: Knowledge representation and inheritance

Taxonomic structure


   \A x . Elephant(x) -> Mammal(x) 
   \A x . Elephant(x) -> color(x) = gray 
   \A x . Penguin(x) -> Bird(x) /\ \neg CanFly(x)
slide: Taxonomies and predicate logic