Experience
Education
Bio
I am a Research Scientist at the University of Texas at Austin and received my PhD at Delft University of Technology in the Netherlands in 2008. My research focuses on solving hard-combinatorial problems in areas such as formal verification, number theory, and extreme combinatorics. Most of my contributions are related to theory and practice of satisfiability (SAT) solving. I have developed award-winning SAT solvers, and my preprocessing techniques are used in state-of-the-art SAT solvers. My current research focusses on two major challenges for SAT solving: 1) exploiting the potential of high-performance computing; and 2) validating the results of SAT solvers and related tools. I have been developing a novel parallel SAT solving paradigm, called cube-and-conquer, which enables linear time speedups on many hard problems. The first publication on cube-and-conquer won the best paper award at HVC 2011. The increasing complexity of SAT solvers and related tools makes it more likely that these tools contain bugs. I designed a new proof format and implemented a fast, corresponding proof checker for SAT and QBF solvers. Proof-logging in this format has been mandatory for the SAT Competitions since 2013, thereby increasing the confidence that tools produce correct results. By constructing and validating a proof for the Boolean Pythagorean Triples problem (200 TB in size), I showed that proof logging and verification is even possible for the hardest problems. I am one of the editors of the Handbook of Satisfiability. This 900+ page handbook has become a standard for the SAT community, and it is a tremendous resource for future scientists. I am an Associate Editor of the Journal on Satisfiability, Boolean Modeling and Computation and was a co-chair of the SAT 2015 conference in Austin.