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

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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.

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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
(http://www.uu.nl/EN/faculties/Humanities/research/researchinstitutes/zeno/research/theoreticalphilosophy/Pages/default.aspx
) of the Philosophy department (http://www.phil.uu.nl/),

and between
   * the more practically oriented PhD student and
   * the more theory oriented postdoc.
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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: http://www.vsnu.nl/Workstudy/Universities-as-employers-/Collective-Labour-Agreement.htm

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

Send your application in pdf (or another non-proprietary format)  to mailto:SciencePenO@uu.nl


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

Mention vacancy nr 62910.