[ The Types Forum (announcements only), 
     http://lists.seas.upenn.edu/mailman/listinfo/types-announce ]

Vacancy PhD student on Realizing Optimal Sharing in the Functional  
Language Implementations
Utrecht University,
The Netherlands.

Within the Software Technology group of the Information and Computing  
Sciences department of Utrecht University there is a vacancy for a PhD  
student to work on  the efficient implementation of functional  
languages. The position is funded by NWO, the Netherlands Organization  
for Scientific Research.

Project summary:

Lambda-calculus and term rewriting are models of computation lying at  
the basis of functional programming languages. Both possess syntactic  
meta-theories based on analyzing rewrite steps. Unfortunately, naive  
implementations are inefficient, since subterms are frequently copied.

To overcome this problem in both theoretical systems and actual  
implementations, duplicate work is avoided by using graph-based term  
representations, in which identical subterms can be (but not always  
are) shared. The question arises whether graph-representations and  
their reductions that are optimal in a theoretical sense can also be  
practical from an implementer's point of view. However, so far it is  
unclear whether nice theoretical ideas combine well with existing  
implementation methods. The overall-goal of this project is to answer  
this question in a back-and-forth communication between theoretical  
concepts and practical realizations. Starting points are the recent  
work on the optimal Lambdascope implementation based on context  
sharing, and the Haskell implementation developed at Utrecht University.

One of the open problems is whether the Lambdascope framework can be  
extended to efficiently represent  sets of mutually recursive  
definitions. Another, whether global program analysis can discover  
where Lambdascope-based approaches solve problems due to insufficient  
sharing. If both questions can be solved, we want to combine  
Lambdascope-based implementations with conventional frameworks, and  
investigate how efficient the resulting implementations become. The  
unique combination of the theoretical depth from the Logic department  
and the implementation skills and compiler infrastructure from the  
Computer Science department make Utrecht University the optimal  
surroundings for such a project.

Project leaders are Prof.dr. Doaitse Swierstra and
dr. Vincent van Oostrom (principal investigator).

The project will be executed in close cooperation between
    * the Software Technology group (http://www.cs.uu.nl/wiki/Center)  
of the Information and Computing Sciences department (http://www.cs.uu.nl/ 
    * and the Theoretical Philosophy group
) of the Philosophy department (http://www.phil.uu.nl/),

and between
    * the more practically oriented PhD student and
    * the more theory oriented postdoc.

Requirements: Master degree in Computer Science, Logic, or equivalent.  
Good knowledge of functional programming, and several advanced  
computer science techniques. Knowledge of lambda-calculus  
implementations, Haskell, and compiler construction will be useful.  
Both theory and software development based on this should appeal to you.

Terms of employment: the PhD student should start as soon as possible,  
but no later than January 1, 2010.  The position is for four years  
(after one year there will be an evaluation), full-time. Gross salary  
starts with € 2042,-- per month in the first year and increases to €  
2612,-- in the fourth year of employment.  The salary is supplemented  
with a holiday bonus of 8% and an end-of-year bonus of 3%.  In  
addition we offer: a pension scheme, partially paid parental leave,  
facilities for child care, flexible employment conditions in which you  
may trade salary for vacation days or vice versa. Conditions are based  
on the Collective Employment Agreement of the Dutch Universities: 

More information:
   * about the project can be found on 
   * about the Software Technology group on http://www.cs.uu.nl/wiki/Center
   * about the Information and Computing Sciences department on 
   * about this vacancy can be obtained from Doaitse Swierstra 
,  +31 6 4613 6929).

Send your application in pdf (or another non-proprietary format)  to 

with a cc to mailto:doai...@cs.uu.nl. on or before Sept 31, 2009.

Mention vacancy nr 62910.

Reply via email to