The Theoretical Computer Science group at KTH Royal Institute of Technology invites applications 
for PhD positions in Theoretical Computer Science with a focus on proof complexity and connections 
to SAT solving.

KTH Royal Institute of Technology is the leading technical university in Sweden, with education 
and research spanning from natural sciences to all branches of engineering including architecture, 
industrial management and urban planning. The Theoretical Computer Science group at KTH
(http://www.csc.kth.se/tcs/) offers a strong research environment covering a wide range of 
research topics such as complexity theory and approximation algorithms, computer and network 
security, cryptography, formal methods and natural language processing. The group has a consistent 
track record of publishing regularly in the leading theoretical computer science conferences and 
journals worldwide, and the research conducted here has attracted numerous international awards 
and grants in recent years.

We are seeking PhD students for the research project "Understanding the Hardness of Theorem Proving"
in the area of proof complexity with connections to SAT solving.

Proving formulas in propositional logic is a problem of immense importance both theoretically and 
practically. On the one hand, this computational task is believed to be intractable in general, and
deciding whether this is so is one of the famous million dollar Millennium Problems (the P vs. 
NP problem). On the other hand, today so-called SAT solvers are routinely used to solve large-scale
real-world problem instances with millions of variables (while there are also small formulas known 
with just a couple of hundreds of variables that cause even state-of-the-art SAT solvers to stumble).

Proof complexity studies formal systems for reasoning about logic formulas. This field has deep 
connections to fundamental questions in computational complexity, but another important motivation 
is the connection to SAT solving. All SAT solvers explicitly or implicitly define a system in which
proofs are searched for, and proof complexity can be seen to analyse the potential and limitations 
of such proof systems (and thereby of the algorithms using them).

This project aims to advance the frontiers of proof complexity, and to leverage this research to 
shed light on questions related to SAT solving. The project is led by Jakob Nordstrom 
(http://www.csc.kth.se/~jakobn) and is financed by a Starting Independent Researcher Grant from 
the European Research Council.

These are full-time positions, normally for five years including 20% teaching, with salary 
according to KTH PhD student regulations (internationally very competitive). The successful 
candidates are expected to start in August 2012, although this is to some extent negotiable.

The application deadline is January 20, 2012 but candidates are encouraged to apply already now. 
See http://www.csc.kth.se/~jakobn/openings/D-2011-0503-Eng.php for the full, formal announcement 
with more information. Informal enquiries about these positions are welcome and may be sent to 
Jakob Nordstrom.