Joost Winter

Welcome to my academic homepage! Until June 2017, I was a postdocoral researcher in the Faculty of Mathematics, Informatics and Mechanics at the University of Warsaw.

Previously I have obtained my PhD degree in Computer Science at the Radboud Universiteit Nijmegen, with a thesis titled Coalgebraic Characterizations of Automata-Theoretic Classes, under supervision of Jan Rutten and Marcello Bonsangue, and a MSc degree in Logic at the ILLC at the University of Amsterdam, with a thesis on transfinite computation, under supervision of Benedikt Löwe.

If you find any mistakes, errors, or unjustly omitted references in any of my papers, please mail me so I can add them to the list of errata!

Research interests

Coalgebra, bialgebra, formal languages and automata theory, formal power series, streams, automatic sequences, category theory, functional programming.

Articles

Joost Winter: A completeness result for finite bisimulations up-to congruence. Presented at CALCO Early Ideas 2017. PDF
Joost Winter: Product rules and distributive laws. In CMCS 2016, pp. 114-135. PDF
Joost Winter: A Yang-Baxter-like condition for distributive laws over endofunctors and co-pointed endofunctors. Presented at CALCO Early Ideas 2015. PDF
Joost Winter: A completeness result for finite λ-bisimulations. In FoSSaCS 2015, pp. 117-132. PDF
Joost Winter, Marcello M. Bonsangue, Jan Rutten: Context-free Coalgebras. In Journal of Computer and System Sciences, 89 (2015), pp. 911-939. PDF Errata
Helle Hvid Hansen, Clemens Kupke, Jan Rutten, Joost Winter: A Final Coalgebra for k-Regular Sequences. In Franck van Breugel et al (eds.), Horizons of the Mind: A Tribute to Prakash Panangaden (2014), pp. 124-145. PDF
Joost Winter, Marcello M. Bonsangue, Jan Rutten: Coalgebraic Characterizations of Context-free Languages. In Logical Methods in Computer Science, Vol. 9 (3:14) (2013). PDF
Jurriaan Rot, Joost Winter: On Language Equations and Grammar Coalgebras for Context-free Languages. Presented at CALCO Early Ideas 2013. PDF
Joost Winter: QStream: A Suite of Streams. In CALCO 2013, pp. 353-358. PDF
Frank de Boer, Michiel Helvensteijn, Joost Winter: A Modal Logic for Abstract Delta Modeling. In SPLC (2) 2012, pp. 45-52. PDF
Baltasar Trancón y Widemann, Joost Winter: Lindenmayer Systems, Coalgebraically. Short contribution, presented at CMCS 2012. PDF
Marcello M. Bonsangue, Jan Rutten, Joost Winter: Defining Context-Free Power Series Coalgebraically. In CMCS 2012: pp. 20-39. PDF Errata
Joost Winter, Marcello M. Bonsangue, Jan Rutten: Context-Free Languages, Coalgebraically. In CALCO 2011: pp. 359-376. PDF
Joost Winter: Is P = PSPACE for Infinite Time Turing Machines? In ILC 2007: pp. 126-137. PDF
Joost Winter: Space Complexity in Infinite Time Turing Machines. MSc Thesis. ILLC MOL-2007-14. PDF

Various

Here you can find an erratum to the proofs of Christol's theorem found in various books.

PhD Thesis

You can view the defended version as well as the accompanying stellingen. Furthermore, I have prepared a list of errata as well as a revised version in which all of these errata have been incorporated.

Presentations

Arden's Rule and the Kleene-Schützenberger Theorem: Presentation given at the ACG, on December 3, 2013. PDF
A Final Coalgebra for the k-regular and k-automatic Sequences: Presentation given at Highlights of Logic, Games and Automata, on September 21, 2013. PDF
QStream: A Suite of Streams: Presentation given at CALCO Tools, on September 3, 2013. PDF
On Language Equations and Grammar Coalgebras for Context-free Languages: Presentation given at CALCO Early Ideas, on September 2, 2013. PDF
Coinductive Stream Calculus in Haskell: Presentation given at the ACG, on June 5, 2013. PDF
Representing algebraic streams using behavioural differential equations: Presentation given at the Representing Streams workshop in Leiden, on December 12, 2012. PDF
Behavioural differential equations: an introduction: Presentation given at ICT Open, on October 23, 2012. PDF
Automatic Sequences as Context-Free Systems: Presentation given at the Dagstuhl seminar on Coalgebraic Logics, on 15 October 2012. PDF
Generalized Context-Freeness: Presentation given at the COIN symposium, on January 23, 2012. PDF
A Coalgebraic View on Context-Free Languages and Streams: Presentation given at the CoRE workshop, on November 8, 2011. PDF
A Coalgebraic View on Context-Free Languages: Presentation given at CALCO '11, on August 31, 2011. PDF
A Coalgebraic View on Context-Free Languages and Streams: Presentation given at the Streams Seminar, on May 10, 2011. PDF
A Coalgebraic View on Context-Free Languages: Presentation given at IPA Lentedagen, on April 7, 2011. PDF
Coalgebra, Coinduction, and Languages: Presentation given at the ACG, on March 2, 2011. PDF

Programming

QStream, a simple tool for coinductive stream specifications, written in Haskell.

For comments, e-mail to <jwinter@mimuw.edu.pl>.

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