84 ;;Quote: an object's methods interact indirectly through its state variables

84+;;Quote: a class' representation invariant captures its assumptions about what state variables mean and how they can change

84 ;;Quote: a class' abstraction relation gives the correspondence between its internal state and its intended conceptual value; e.g., does a stack grow up or down

84 ;;Quote: representation inheritance is white-box inheritance that conforms to representation invariants and abstraction relations

86 ;;Quote: use representation inheritance for efficient implementation of new operations; e.g., swap the tails of two lists without cross links or missed elements

89 ;;Quote: every class should include a method to test its representation invariant; use to test and stress test representation inheritance

90 ;;Quote: with white box inheritance, need to retest all inherited methods and all superclasses

90+;;Quote: with representation inheritance, do not need to retest the superclass; as long as its representation invariant and abstraction relation are correctly maintained