I obtained the habilitation degree at the Technical University of Vienna in March 2008. My habilitation thesis consists of the following six papers and preface. (Some of the papers were revised after the thesis was submitted in May 2007.)

- Front plus preface of the thesis. [postscript] [pdf]
- S. A. Terwijn,
*Constructive logic and the Medvedev lattice*, Notre Dame Journal of Formal Logic 47(1) (2006) 73-82. [postscript] [pdf] - S. A. Terwijn,
*The Medvedev lattice of computably closed sets*, Archive for Mathematical Logic 45(2) (2006) 179-190. [postscript] [pdf] - S. A. Terwijn,
*Kripke models, distributive lattices, and Medvedev degrees*, Studia Logica 85(3) (2007) 327--340. Preliminary version in Proceedings of Computability in Europe (CiE 2005), Lecture Notes in Computer Science 3526, 486-494, Springer, 2005. [postscript] [pdf] - A. Sorbi and S. A. Terwijn,
*Intermediate logics and factors of the Medvedev lattice*, Annals of Pure and Applied Logic 155 (2008) 69-85. [postscript] [pdf] - S. A. Terwijn,
*On the structure of the Medvedev lattice*, Journal of Symbolic Logic 73(2) (2008) 543-558. [postscript] [pdf] - S. A. Terwijn,
*The finite intervals of the Muchnik lattice*, Transactions of the American Mathematical Society 364 (2012) 2521-2538. [postscript] [pdf]