Research: Member of the research program Algorithms and Software Technology; Member of the group Theoretical Computer Science。 Publications: J. Engelfriet; Two-way pebble transducers for partial functions and their composition, Acta Informatica online, March 2015 doi:10.1007/s00236-015-0224-3 。 J. Engelfriet; Context-free grammars with storage CoRR abs/1408.0683. Revised version of Report 86-11, Department of Computer Science, University of Leiden, July 1986。 J. Engelfriet, S. Maneth, H. Seidl; How to remove the look-ahead of top-down tree transducers, in: DLT 2014 (A.M. Shur and M.V. Volkov, editors), Lecture Notes in Computer Science 8633, Springer-Verlag, 2014, pp.103-115。 M. Benedikt, J. Engelfriet, S. Maneth; Determinacy and rewriting of top-down and MSO tree transformations, in: MFCS 2013 (K. Chatterjee and J. Sgall, editors), Lecture Notes in Computer Science 8087, Springer-Verlag, 2013, pp.146-158。 B. Courcelle, J. Engelfriet; Graph Structure and Monadic Second-Order Logic, a Language-Theoretic Approach; Encyclopedia of Mathematics and its Applications, vol. 138, Cambridge University Press, June 2012 (728 pages) 20% discount , book-website。 A. Maletti, J. Engelfriet; Strong lexicalization of tree adjoining grammars, Proc. 50th Annual Meeting Association for Computational Linguistics (ACL 2012), pages 506-515, 2012 online, slides。 F. Drewes, J. Engelfriet; The generative power of delegation networks, Report UMINF 12.15, Umeå University, 2012 pdf-file. To appear in Information and Computation。 J. Engelfriet, E. Lilin, A. Maletti; Extended multi bottom-up tree transducers -- Composition and decomposition, Acta Informatica 46 (2009), 561-590 online authorcopy。 J. Engelfriet, S. Maneth, H. Seidl; Deciding equivalence of top-down XML transformations in polynomial time, J. of Comp. Syst. Sci. 75 (2009), 271-286 online。 J. Engelfriet; The time complexity of typechecking tree-walking tree transducers, Acta Informatica 46 (2009), 139-154 online authorcopy。