Contact Email: 

Research interests
I mostly work on the field of Functional Programming, especially Haskell, and don’t mind some sidelooks into formal verficiation and theorem proving.
Current Position
I have moved on and taken a postdoc position at the University of Pennsylvania in Philadelphia, where I have a institutional webpage. You might also be interested in my
Activitis
 Program Committee Chair of Haskell in Leipzig 2016.
 Program Committee Member of Haskell Implementors Workshop 2016.
 Reviewer for AMS
Courses
 Laboratory: Theorem prover lab: applications in programming languages , Sommersemester 2016, Bestes Praktikum
 Lecture: Semantics of programming languages , Sommersemester 2015, Beste Wahlvorlesung
 Laboratory: Theorem prover lab: applications in programming languages , Sommersemester 2013, Bestes Praktikum
 Common Excercises: Tutorial for Semantics of programming languages , Sommersemester 2012
Publications
2018

Illi Isabellistes Se Custodes Egregios Praestabant
Principled Software Development: Essays Dedicated to Arnd PoetzschHeffter on the Occasion of his 60th Birthday 2018, pp. 267282 : S. Bischof, J. Breitner, D. Lohner, G. Snelting 
LowDeterministic Security For LowNondeterministic Programs
Journal of Computer Security 2018, pp. 335366 : S. Bischof, J. Breitner, J. Graf, M. Hecker, M. Mohr, G. Snelting
2017

Der Grader Praktomat
Automatisierte Bewertung in der Programmierausbildung 2017, pp. 159172 : J. Breitner, M. Hecker, G. Snelting
2016

Safe zerocost coercions for Haskell
Journal of Functional Programming July 2016 : J. Breitner, R. Eisenberg, S. P. Jones, S. Weirich 
Surprise Paradox
Archive of Formal Proofs July 2016 : J. Breitner 
The meta theory of the Incredible Proof Machine
Archive of Formal Proofs May 2016 : J. Breitner, D. Lohner 
Lazy Evaluation: From natural semantics to a machinechecked compiler transformation
April 2016 : J. Breitner 
On Improvements Of LowDeterministic Security
Principles of Security and Trust  5th International Conference, POST 2016, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2016, Eindhoven, The Netherlands, April 28, 2016, Proceedings 2016, pp. 6888 (POST 16) : J. Breitner, J. Graf, M. Hecker, M. Mohr, G. Snelting 
Visual theorem proving with the Incredible Proof Machine
Interactive Theorem Proving 2016 (ITP 2016) : J. Breitner
2015

Punktgenau  MultimediaSpielzeug Tiptoi selbst programmieren
December 2015, pp. 108114 : J. Breitner, C. Podszun 
Stiftzauber  Eigene Bücher und Spiele für den Tiptoi vertonen
March 2015, pp. 156159 : J. Breitner, C. Podszun 
The Safety of Call Arity
Archive of Formal Proofs February 2015 : J. Breitner 
Call Arity
Trends in Functional Programming 2015, pp. 3450 (TFP 2014) : J. Breitner 
Formally Proving a Compiler Transformation Safe
Haskell 2015 (Haskell'15) : J. Breitner
2014

The Correctness of Launchbury's Natural Semantics for Lazy Evaluation
ArXiv eprints May 2014 : J. Breitner 
Safe Zerocost Coercions for Haskell
ICFP 2014 (ICFP 2014) : J. Breitner, R. Eisenberg, S. P. Jones, S. Weirich
2013

Certified HLints with Isabelle/HOLCFPrelude
ArXiv eprints June 2013 : J. Breitner, B. Huffman, N. Mitchell, C. Sternagel 
The Correctness of Launchbury's Natural Semantics for Lazy Evaluation
Archive of Formal Proofs January 2013 : J. Breitner
2012

dup  Explicit unsharing in Haskell
ArXiv eprints July 2012 : J. Breitner 
Tackling the testing migration problem with SATSolvers
ArXiv eprints April 2012 : J. Breitner 
The ghcheapview package
March 2012 : J. Breitner
2011

Loop subgroups of F_{r} and the image of their stabilizer subgroups in GL_{r}(Z)
Israel Journal of Mathematics December 2011, pp. 113 : J. Breitner 
The General Triangle Is Unique
Archive of Formal Proofs April 2011 : J. Breitner
2010

Shivers' Control Flow Analysis
Archive of Formal Proofs November 2010 : J. Breitner 
Control Flow in Functional Languages  Formally taming lambdas
November 2010 : J. Breitner 
The shiverscfg package
November 2010 : J. Breitner 
Loop subgroups of F_{r} and the images of their stabilizer subgroups in GL_{r}(Z)
February 2010 : J. Breitner
Projects
Advised thesis projects
finished
 Call Arity vs. Demand Analysis, masters thesis
 Open inductive predicates, masters thesis
 Qualitative Modelling of Biological Signalling Pathways using SATsolving in Prolog, bachelor thesis
 Modeling Uncertain Data using Monads and an Application to the Sequence Alignment Problem, bachelor thesis
 Inferring equalities in functional programs, bachelor thesis
 Visualization of Lazy Evaluation and Sharing, bachelor thesis
Theses worked on
 Verifiying Shiver's functional CFA analysis (finished), study thesis
Talks and further publications can be found on my private publication page.