Research Interests
My research interests focus on logic, automated reasoning and term rewriting. For my PhD, I investigated variants of KnuthBendix completion combining a multicompletion approach with the use of automatic termination tools (this poster provides an overview). For standard, ordered, and normalized completion I implemented this method in the tool mkbtt. I also worked on SMT encodings for the simple and elegant completion tool maxcomp, see here.Recently, I was employed on the project Constrained Rewriting and SMT, contributing forbidden patterns and unraveling results to CeTA/IsaFor.
More recently, I did an internship at Microsoft Research Cambridge, developing a verifier for the programming language Dafny called Selfy, which can help you to find (loop) invariants.
Some code can also be found on github.
Publications
Journal Articles

A. Yamada, S. Winkler, N. Hirokawa, and A. Middeldorp
ACKBO Revisited (preprint)
Theory and Practice of Logic Programming, 2015. © Cambridge University Press 
H. Zankl, S. Winkler, and A. Middeldorp
Beyond Polynomials and Peano Arithmetic – Automation of Elementary and Ordinal Interpretations (preprint)
Journal of Symbolic Computation, 69, 129158, 2015. © Elsevier 
S. Winkler, H. Sato, A. Middeldorp, and M. Kurihara
MultiCompletion with Termination Tools (preprint)
Journal of Automated Reasoning, 50(3), 317354, 2013. © Springer
Papers in Proceedings

S. Winkler and R. Thiemann
Formalizing Soundness and Completeness of Unravelings
In FroCoS 2015, to appear. 
H. Sato and S. Winkler
Encoding DP Techniques and Control Strategies for Maximal Completion
In CADE 25, to appear. 
T. Sternagel, S. Winkler, and H. Zankl
Recording Completion for Certificates in Equational Reasoning
In CPP 2015, ACM, pp. 4147, 2015 
J. Nagele, R. Thiemann, and S. Winkler
Certification of Nontermination Proofs using Strategies and Nonlooping Derivations
In 6th VSTTE, LNCS 8471, pp. 216232, 2014. 
A. Yamada, S. Winkler, N. Hirokawa, and A. Middeldorp
ACKBO Revisited (report version)
In 12th FLOPS, LNCS 8475, pp. 319335, 2014. 
S. Winkler and A. Middeldorp
Normalized Completion Revisited
In 24th RTA, LIPIcs 21, pp 319334, 2013. 
S. Winkler, H. Zankl, and A. Middeldorp
Beyond Peano Arithmetic  Automatically Proving Termination of the Goodstein Sequence
In 24th RTA, LIPIcs 21, pp 335351, 2013. 
S. Winkler, H. Zankl, and A. Middeldorp
Ordinals and KnuthBendix Orders
In LPAR18, LNCS 7180, pp 420434, 2012. ©SpringerVerlag 
S. Winkler and A. Middeldorp
AC Completion with Termination Tools
In CADE 23, LNCS (LNAI) 6803, pp 492498, 2011. ©SpringerVerlag 
S. Winkler and A. Middeldorp
Termination Tools in Ordered Completion
In IJCAR 2010, LNCS (LNAI) 6173, pp. 518532, 2010. ©SpringerVerlag 
S. Winkler, H. Sato, A. Middeldorp, and M. Kurihara
Optimizing mkbTT (System Description)
In 21st RTA, LIPIcs 13, pp 373384, 2010. CreativeCommons 
H. Sato, S. Winkler, M. Kurihara, and A. Middeldorp
Multicompletion with Termination Tools (System Description)
In IJCAR 2008, LNCS (LNAI) 5195, pp. 306312, 2008. ©SpringerVerlag
Thesis

S. Winkler
Termination Tools in Automated Reasoning
PhD thesis, University of Innsbruck, 2013.
Workshops

H. Sato and S. Winkler
A Satisfiability Encoding of Dependency Pair Techniques for Maximal Completion
In Proceedings of the 14th International Workshop on Termination (WST 2014),
pp 8084, 2014. 
H. Zankl, S. Winkler and A. Middeldorp
Automating Elementary Interpretations
In Proceedings of the 14th International Workshop on Termination (WST 2014),
pp 9094, 2014. 
H. Zankl, S. Winkler and A. Middeldorp
Automating Ordinal Interpretations
In Proceedings of the 12th International Workshop on Termination (WST 2012),
pp 9498, 2012. 
H. Sato, S. Winkler, M. Kurihara, and A. Middeldorp
ConstraintBased MultiCompletion Procedures for Term Rewriting Systems
In IEICE Transactions on Information and Systems E92D (2), pp 220234, 2009 
C. Sternagel, R. Thiemann, S. Winkler, and H. Zankl
CeTA – A Tool for Certified Termination Analysis
In Proceedings of the 10th International Workshop on Termination (WST 2009),
pp 8487, 2009.