Summary: Lehr- und Forschungsgebiet Informatik 2
Zeit: Montag, 08.12.2008, 14.30 Uhr
Ort: Raum 6019, Ahornstr. 55
Referent: Prof. Dr. Michael Codish
Ben-Gurion University, Beer-Sheva/Israel
Titel: Proving Termination with Size Change Graphs:
Theory, Practice & (Boolean) Satisfaction
Size change graphs provide an abstract mathematical representation which de-
scribes how the size of "the data" changes in the transitions made by a given pro-
gram. Size change graphs provide also a basis to reason about the termination of the
programs they describe.
I will present two techniques to prove termination based on size change graphs: the
more standard "global approach" and the more interesting "local approach". I will
show the correctness result for the local approach which applies Ramsey's Theorem.
I will also show a completeness result which states that for a given set of size change
graphs, if there exists any proof of termination then there exists one of a very simple
form. Here hides one main advantage of the local approach: Size change termination
is decidable and easy to automate.