Editing Liskov substitution principle (section)

== Origins ==
The rules on pre- and postconditions are identical to those introduced by Bertrand Meyer in his 1988 book ''[[Object-Oriented Software Construction]]''. Both Meyer, and later Pierre America, who was the first to use the term ''behavioral subtyping'', gave [[proof-theoretic]] definitions of some behavioral subtyping notions, but their definitions did not take into account [[Aliasing (computing)|aliasing]] that may occur in programming languages that support references or pointers. Taking aliasing into account was the major improvement made by Liskov and Wing (1994), and a key ingredient is the history constraint. Under the definitions of Meyer and America, a mutable point would be a behavioral subtype of an immutable point, whereas Liskov substitution principle forbids this.