Title: 
     Selective Open Recursion: A Solution to the Fragile Base Class Problem

Presented by Kevin Donnelly.

Abstract: 
     Current object-oriented languages to not fully protect the implementation 
details of a class from its subclass, making it difficult to change the 
implementation without breaking subclasses.  The fragile base class problem is 
caused by the default use of open recursion semantics (which complicates local 
reasoning) even when this semantics is not needed.  Previous solutions to the 
fragile base class problem involve speficying more implementation details, 
while our solution allows one to hide more of these details.  Our proposal 
changes the default self-call semantics to static dispatch while allowing the 
programmer to specify which methods aught to use open recursion.  I will 
present a small language, Featherwight OpenJava, and show how this new 
semantics can be used to prove an abstraction theorem.