[ Contact info ] [ Research
interests ] [ Teaching ] [ Publications and preprints ] [ Presentations at conferences ]
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 Johan Öinert
PhD and Reader in Mathematics
(På svenska: Teknologie doktor och docent i matematik)




Professor of Mathematics 




Contact info
Research interests
 Noncommutative algebra: Crossed products [1] [2] and more
generally graded rings [3]
[4] [5]. Ore extensions [6].
 Dynamical systems: Minimal dynamical systems and groupoid C*dynamical systems.
 The interplay between dynamical systems and C*algebras, and various algebraic constructions.
 Crossed product Banach algebras. (More details here.)
Click here to see the Wordle image generated from my thesis abstract.
 Ickekommutativ algebra: Korsprodukter och graderade ringar i största allmänhet. Oreutvidgningar.
 Dynamiska system: Minimala dynamiska system och gruppoid C*dynamiska system.
 Samspelet mellan dynamiska system och C*algebror, och diverse algebraiska konstruktioner.
 Banachkorsprodukter. (Mer detaljer här.)
En populärvetenskaplig beskrivning på svenska kommer postas här, i sinom tid...
I am a member of the research group in Algebra and Geometry at Blekinge Institute of Technology .
In the past, I have been a member of the research groups in Noncommutative Geometry and Applications respectively Algebra, at Lund University (20122014),
the research group in Noncommutative Geometry
within the Centre for Symmetry and Deformation
at the University of
Copenhagen (20102012),
the research group in Noncommutative Geometry and Applications
at Lund University (20082010)
and the research group in
Algebra and Geometry at the University of Antwerp (20062008).
My favourite open problems
A common belief (amongst nonmathematicians) is that mathematics is a finished subject, that there is nothing more to explore.
However, the real situation is quite the opposite. There are plenty of important problems
that are open in the sense that noone has been able to solve them.
Here is a list of my favourite open problems/conjectures:
 Kaplansky's idempotent/zerodivisor/unit conjecture for group rings (A counterexample to the unit conjecture was provided by Gardam in 2021. See arXiv.)
 The KadisonKaplansky conjecture
 The BaumConnes conjecture
 The Goldbach conjecture
The KadisonSinger problem, Solved in 2013 by Marcus, Spielman and Srivastava!!!, arXiv:1306.3969 [math.CO]
 Köthe's conjecture
 The Riemann hypothesis
(Shortly, I will try to write out some more details about these problems.)
Students, collaborators, genealogy etc.
My coauthors include
My Erdös number is 4 and my Einstein number is 5 (take a look here!).
 I have been assistant supervisor for Johan
Richter , who was a PhD student at
Lund University.
Johan defended his licentiate thesis on October 5, 2012,
and his doctoral thesis on September 29, 2014.
His PhD thesis, entitled ''Algebraic Properties of Ore Extensions and Their Commutative Subrings'', can be found here.
 I have been a mentor for Sanaz Pooya , who is a PhD student at Ferdowsi University of Mashhad, Iran,
and who was visiting Lund University for 10 months (September 2013June 2014)
as a guest PhD student with an Erasmus Mundus (SALAM) scholarship.
 I have supervised Bartosz Malman , who presented his master's thesis,
entitled ''Zerodivisors and idempotents in group rings'',
on August 28, 2014.
The thesis can be downloaded from here.

I have been a mentor for Mai Hoang Bien , who was a postdoctoral researcher at Blekinge Institute of Technology during 10 months (January 2016October 2016).

I am a mentor for Stefan Wagner , who is a postdoctoral researcher at Blekinge Institute of Technology since June 2017.
 I am supervising Daniel Lännström , who is a PhD student
at Blekinge Institute of Technology.
Daniel defended his licentiate thesis, entitled
"The structure of epsilonstrongly graded rings with applications to Leavitt path algebras and CuntzPimsner rings",
on May 15, 2019.
It can be found here.
He has authored three
interesting research papers which you can find
here,
here,
and
here.
 I have been a mentor for Samaneh Baghdari , who is a PhD student at Isfahan University of Technology, Iran, and who was visiting Blekinge Institute of Technology for 6 months (September 2018February 2019) as a guest PhD student.
In the autumn of 2012, I participated in the Leavitt Path Algebra Seminar
at the Centre for Symmetry and Deformation, University of Copenhagen.
People that I like to keep track of:
Gergely Berczi,
Viola Bruni,
Vladimir Dotsenko,
Alex Engström ,
Ghislain Fourier,
Magnus Goffeng,
Isar Goyvaerts,
Jonas Hartwig,
Daniel Larsson,
Javier Lopez Pena,
Douglas
Lundholm,
Samuel
Lundqvist,
Ehud Meir,
Tomas Persson,
Anne Pichereau,
Artur Ruuge,
Karl Rökaeus,
Isar Stubbe,
Christian Svensson,
Jacob Sznajdman,
Bogdan Toader,
Fred Van Oystaeyen,
Qimh
Xantcha.
Teaching
(DS=Datorsäkerhet, IE=Industriell ekonomi, MT=Maskinteknik, SP=Spel och programvaruteknik)
Publications and preprints
Theses
 J. Öinert,
"Connections between Topological Dynamical Systems and NonCommutative C*Algebras", v+102 pp.,
Master's Theses in Mathematical Sciences 2005:E35,
ISSN 14046342, LUTFMA31232005, Lund University, 2005.
 J. Öinert,
"Ideals and Maximal Commutative Subrings of Graded
Rings", xii+171 pp.,
Doctoral Theses in Mathematical Sciences 2009:5,
ISSN 14040034,
LUTFMA10382009, ISBN 9789162878320, Lund University, 2009.
Errata
If you have trouble accessing any of the papers below,
please send me an email and I will do my best to try to help you!
Accepted papers
 J. Öinert and S. Silvestrov,
''Commutativity and Ideals in
Algebraic Crossed
Products'',
Journal of Generalized Lie Theory and Applications, Vol. 2, No. 4, pp. 287302
(2008)
 J. Öinert and S. Silvestrov,
''On a Correspondence Between
Ideals and
Commutativity in Algebraic Crossed Products'',
Journal of Generalized Lie Theory and Applications, Vol. 2, No. 3, pp. 216220
(2008)
 J. Öinert and S. Silvestrov,
''Crossed ProductLike and
PreCrystalline
Graded Rings'',
Chapter 24 in "Generalized Lie Theory in Mathematics,
Physics and Beyond", Silvestrov, S.; Paal, E.; Abramov, V.; Stolin, A. (Eds.), 16pp., Springer (2009) [ publisher's web
site ]
 J. Öinert and S. Silvestrov,
"Commutativity and Ideals in PreCrystalline Graded
Rings",
Acta Applicandae Mathematicae, Vol. 108, No. 3, pp. 603615
(2009) [ publisher's website ]
 J. Öinert, S. Silvestrov, T. TheohariApostolidi and H. Vavatsoulas,
"Commutativity and Ideals in Strongly Graded
Rings",
Acta Applicandae Mathematicae, Vol. 108, No. 3, pp. 585602
(2009) [ publisher's website ]
 J. Öinert,
"Simple Group Graded Rings and Maximal
Commutativity",
Contemporary Mathematics (American Mathematical Society), Vol. 503, pp. 159175 (2009)
 J. Öinert and P. Lundström,
"Commutativity and Ideals in Category Crossed
Products",
Proceedings of the Estonian Academy of Sciences, Vol. 59, No. 4,
pp. 338346 (2010)
 J. Öinert and P. Lundström,
"The Ideal Intersection
Property for Groupoid Graded Rings",
Communications in
Algebra, Vol. 40, No. 5, pp. 18601871 (2012) [ publisher's
website ]
 J. Öinert and P. Lundström,
"Miyashita Action in Strongly Groupoid Graded Rings",
International Electronic Journal of
Algebra, Vol. 11, pp. 4663 (2012)
 P. Lundström and J. Öinert,
"Skew category algebras associated with partially defined dynamical
systems",
International Journal of Mathematics, Vol. 23, No. 4, pp.
16 (2012) [ publisher's website ]
 J. T. Hartwig and J. Öinert,
"Simplicity and maximal commutative subalgebras of twisted generalized Weyl algebras",
Journal of Algebra, Vol. 373, 312339 (2013) [ publisher's website ]
 J. Öinert, J. Richter and S. Silvestrov,
"Maximal commutative subrings and simplicity of Ore extensions",
Journal of Algebra and Its Applications, Vol. 12, No. 4, 1250192, 16 pp. (2013) [ publisher's website ]
 J. Öinert,
"Simplicity of skew group rings of abelian groups",
Communications in Algebra, Vol. 42, No. 2, 831841 (2014). [ publisher's website ]
 P. Nystedt and J. Öinert,
"Simple skew category algebras associated with minimal partially defined dynamical systems",
Discrete and Continuous Dynamical Systems  Series A (DCDSA), Vol. 33, No. 9, 41574171 (2013) [ publisher's website ]
 P. Nystedt and J. Öinert,
"Simple rings and degree maps",
Journal of Algebra, Vol. 401, 201219 (2014) [ publisher's website ]
 D. Gonçalves, J. Öinert and D. Royer,
"Simplicity of partial skew group rings with applications to Leavitt path algebras and topological dynamics",
Journal of Algebra, Vol. 420, 201216 (2014) [ publisher's website ]
 P. Nystedt and J. Öinert,
"Simple semigroup graded rings",
Journal of Algebra and Its Applications, Vol. 14, No. 7, 1550102, 10 pp. (2015) [ publisher's website ]
 P. Nystedt and J. Öinert,
"Outer partial actions and partial skew group rings",
Canadian Journal of Mathematics, Vol. 67, No. 5, 11441160 (2015) [ publisher's website ]
[ Preprint available @ arXiv ]
 P. Nystedt, J. Öinert and J. Richter,
"Nonassociative Ore Extensions",
Israel Journal of Mathematics, Vol. 224, No. 1, 263292 (2018) [ publisher's website ]
[ Preprint available @ arXiv ]
 Mai Hoang B. and J. Öinert,
"Quasiduo differential polynomial rings",
Journal of Algebra and Its Applications, Vol. 17, No. 4, 11 pp. (2018) [ publisher's website ]
[ Preprint available @ arXiv ]
 J. Öinert,
"Bimodules in group graded rings",
Algebras and Representation Theory, Vol. 20, No. 6, 14831494 (2017) [ publisher's website ]
[ Preprint available @ arXiv ]
 P. Nystedt, J. Öinert and H. Pinedo,
"Artinian and noetherian partial skew groupoid rings",
Journal of Algebra, Vol. 503, 433452 (2018) [ publisher's website ]
[ Preprint available @ arXiv ]
 P. Nystedt, J. Öinert and H. Pinedo,
"Epsilonstrongly graded rings, separability and semisimplicity",
Journal of Algebra, Vol. 514, 124 (2018) [ publisher's website ]
[ Preprint available @ arXiv ]
 V. Beuter, D. Gonçalves, J. Öinert and D. Royer,
"Simplicity of skew inverse semigroup rings with applications to Steinberg algebras and topological dynamics",
Forum Mathematicum, Vol. 31, No. 3, 543562 (2019) [ publisher's website ]
[ Preprint available @ arXiv ]
 P. Nystedt, J. Öinert and H. Pinedo,
"Epsilonstrongly groupoidgraded rings, the Picard inverse category and cohomology",
Glasgow Mathematical Journal, Vol. 62, 233259 (2020)
[ Preprint available @ arXiv ]
 P. Nystedt, J. Öinert and J. Richter,
"Simplicity of Ore monoid rings",
Journal of Algebra, Vol. 530, 6985 (2019)
[ Preprint available @ arXiv ]
 P. Nystedt and J. Öinert,
"Group gradations on Leavitt path algebras",
Journal of Algebra and Its Applications, Vol. 19, No. 9, 16 pp. (2020)
[ Preprint available @ arXiv ]
 P. Nystedt and J. Öinert,
"Simple graded rings, nonassociative crossed products and CayleyDickson doublings",
Journal of Algebra and Its Applications, Vol. 19, No. 12, 22 pp. (2020)
[ Preprint available @ arXiv ]
 P. Nystedt and J. Öinert,
"Strongly graded Leavitt path algebras",
To appear in Journal of Algebra and Its Applications.
[ Preprint available @ arXiv ]
Publications on mathematics education
 J. Öinert,
"Planning and implementing mathematics lectures for firstyear university students  30 tips and tricks",
Chapter 1 in "Improving University Science Teaching and Learning  Pedagogical Projects 2012", Vol. 5, No. 1,
Ulriksen, L; Sølberg, J; Wase Hansen, H. (Eds.), pp. 317, Department of Science Education, University of Copenhagen (2013)
Preprints
 J. Öinert and S. Wagner,
"Complex group rings of group extensions".
[ Preprint available @ arXiv ]
 J. Öinert,
"Units, zerodivisors and idempotents in rings graded by torsionfree groups", submitted.
[ Preprint available @ arXiv ]

D. Lännström, P. Lundström, J. Öinert and S. Wagner,
"Prime group graded rings with applications to partial crossed products and Leavitt path algebras", submitted.
[ Preprint available @ arXiv ]
more coming soon...
Partial lists of my articles can be found on the arXiv, the Zentralblatt MATH and the MathSciNet.
Google scholar keeps track of citations of my articles.
Presentations and attendances at conferences, workshops and
seminars
 3rd Øresund Symposium in Noncommutative Analysis
and Noncommutative Geometry,
January 30, 2004, Lund, Sweden
 Erasmus Intensive Program in Geometric and Algebraic Methods
in Physics and Applications,
September 415, 2005, Antwerp, Belgium
 Lie Days in Martina Franca, "Flags, Quivers and Invariant Theory
in Lie Representation Theory",
May 2227, 2006, Martina Franca (Taranto), Italy
 Socrates Intensive Program in Geometric and Algebraic Methods
in Physics and Applications,
September 418, 2006, Antwerp, Belgium
 International Congress: New Techniques in Hopf Algebras and Graded
Ring
Theory,
September 1923, 2006, Brussels, Belgium
 Algebra, Geometry & Mathematical Physics, BalticNordic Network
Workshop,
October 1214, 2006, Lund, Sweden
(Gave a talk.)
 Operator Methods in Fractal Analysis, Wavelets and Dynamical
Systems,
December 27, 2006, Banff, Canada
(Gave a talk.)
 Algebraic and Geometric Representation Theory (AGLT),
Århus, Denmark,
June
2529, 2007
 Socrates Intensive Program in Geometric & Algebraic Methods with
Applications in Physics,
Antwerpen, Belgium, August 27September 9, 2007
 International Conference on Noncommutative Rings and Geometry in
Honour of
the
60th Birthday of Freddy Van Oystaeyen,
Almeria, Spain,
September 1823,
2007
 Workshop on Interpolation Theory,
Lund, Sweden,
October 8, 2007
(Gave a talk.)
 Algebra, Geometry & Mathematical Physics, BalticNordic Network
Workshop,
Göteborg,
Sweden, October 1113, 2007
(Gave a talk.)
 Svenska Matematikersamfundets Höstmöte,
Växjö, Sweden, November
30December 1, 2007
 LieGrits Workshop,
Oxford, UK, January 39, 2008
 EMS Joint Mathematical Weekend,
Copenhagen, Denmark, February 29March
2,
2008
 5th Øresund Symposium on Noncommutative Analysis
and Noncommutative Geometry,
Copenhagen, Denmark, April 10, 2008
(Gave a talk.)
 The Tribute Workshop in Honour of Professor Gunnar
Sparr,
Lund,
Sweden,
May 89, 2008
 Summer School: 'Symbolic Dynamics and Homeomorphisms of the Cantor
Set',
Copenhagen, Denmark, June 2327, 2008
 5th European Congress of
Mathematics,
Amsterdam, The Netherlands, July 1418, 2008
 Operator Structures and Dynamical Systems,
Lorentz Center, Leiden, The Netherlands, July 2125, 2008 (Gave a talk.)
 Algebra, Geometry & Mathematical Physics, BalticNordic Network
Workshop,
Tartu, Estonia, October 911, 2008 (Gave a talk.)
 NordicÖresund workshop: INANGA, "Inequalities, Interpolation, Noncommutative Analysis, Noncommutative Geometry and
Applications",
Lund, Sweden, November 1718, 2008 (Gave a talk.)
 Svenska Matematikersamfundets Höstmöte,
Linköping, Sweden, November 2829, 2008 (Gave a talk.)
 Socrates Intensive Program in Geometric & Algebraic Methods with Applications in
Physics,
Antwerpen, Belgium, July 619, 2009
 PhD thesis defense,
Lund, Sweden, August 17, 2009
[The thesis may be downloaded here!]
 Topics in Mathematical Physics and Operator Algebra,
September 7, 2009, Copenhagen, Denmark (Gave a talk.)
 Master Class on Von Neumann Algebras and Group
Actions,
January 2529, 2010, Copenhagen, Denmark
 Workshop on Von Neumann Algebras and Group Actions,
February 15, 2010, Copenhagen, Denmark
 NestFest  Conference in Honor of Ryszard Nest's 60th
Birthday,
September 25, 2010, Copenhagen, Denmark
 Intensive Program on Interpolation and Noncommutative
Integration,
September 30October 5, 2010, Lund, Sweden
 Operator Algebras and Representation Theory: Frames, Wavelets and
Fractals,
October 810, 2010, Banff, Canada
 Algebra, Geometry & Mathematical Physics, BalticNordic Network
Workshop,
October 2531, 2010, Tjärnö, Sweden (Gave a talk.)
 Operator Algebras and Representation Theory: Frames, Wavelets and
Fractals,
March 27April 2, 2011, Oberwolfach, Germany
 Joint OsloTrondheim operator algebra seminar,
May 3031,
2011, Trondheim, Norway (Gave a talk.)
 Hopf
algebras and tensor categories,
July 48, 2011, Almeria, Spain
 NordForsk Network Junior Workshop: Operator algebras and
dynamical systems,
September 1417, 2011, Copenhagen, Denmark
 Workshop in honor of Kirchberg's 65th
birthday,
November 1013, 2011, Copenhagen, Denmark
 Master Class on The Nuclear Dimension of C*algebras,
November 1418, 2011, Copenhagen, Denmark
 Workshop: Matematiken i
civilingenjörsutbildningarna  Ett seminarium tillägnat
LarsChrister Böiers i samband med hans pensionering,
November 16, 2011, Lund, Sweden
 NordForsk Network Closing Conference: Operator algebras and dynamical
systems,
May 1520, 2012, Gjógv, Faroe Islands (Gave a talk.)
 Miniworkshop: Commutative subalgebras, ideals and actions
July 2324, 2012, Lund, Sweden (Gave a talk.)
 26th Nordic and 1st EuropeanNordic Congress of Mathematicians (Dedicated to the memory of Lars Hörmander)
June 1013, 2013, Lund, Sweden (Gave a talk.)
 Banach Algebras and Applications,
July 29  August 4, 2013, Gothenburg, Sweden
 Masterclass on Ergodic Theory and von Neumann algebras,
October 1418, 2013, Copenhagen, Denmark
 Öresundsdagen om grundkurser i matematik på universitet och högskolor,
October 23, 2013, Lund, Sweden
 Docentföreläsning, PDF coming soon.
December 12, 2013, Lund, Sweden
 Análise funcional geométrica e ações de grupos,
February 1921, 2014, Florianópolis, Brazil (Gave a talk.)
 The Renaissance Combinatorics Seminar,
April 29, 2014, Helsinki, Finland (Gave a talk.)
 The 8th Øresund symposium on noncommutative analysis and noncommutative geometry,
May 15, 2014, Lund, Sweden
 Den 12:e Sydostkonferensen om matematik,
August 25, 2015, Karlskrona, Sweden (Gave a talk.)
 The 2nd Workshop on Dynamics, Numeration and Tilings (FloripaDynSys II),
December 1112, 2015, Florianópolis, Brazil (Gave a talk.)
 Brauer groups, Hopf algebras and monoidal categories,
in honour of Stef Caenepeel on the occasion of his 60th birthday,
May 2327, 2016, Turin, Italy
 Kleindagarna @ Institute MittagLeffler,
June 1012, 2016, Stockholm, Sweden (Gave a talk.)
 Den 13:e Sydostkonferensen i matematik,
August 25, 2016, Växjö, Sweden
 The MAM seminar,
October 26, 2016, Västerås, Sweden (Gave a talk.)
 The joint UCLULBVUB seminar on quantum groups, Hopf algebras and monoidal categories,
February 20, 2017, LouvainlaNeuve, Belgium (Gave a talk.)
 The 3rd Workshop on Dynamics, Numeration, Tilings and Graph Algebras (FloripaDynSys III),
March 2024, 2017, Florianópolis, Brazil (Gave a talk.)
 Installationsföreläsning (Eng: Inaugural lecture),
May 18, 2017, Karlskrona, Sweden
 Den 14:e Sydostkonferensen i matematik,
August 22, 2017, Karlskrona, Sweden (Gave a talk.)
 International Conference on Stochastic Processes and Algebraic Structures, in honour of Dmitrii S. Silvestrov on the occasion of his 70th birthday,
October 46, 2017, Västerås and Stockholm, Sweden (Gave a talk.)
 Den 15:e Sydostkonferensen i matematik,
August 28, 2018, Växjö, Sweden (Gave a talk.)
 The 1st SNAG meeting,
September 2728, 2018, Linköping, Sweden (Gave a talk.)
 Den 2:a Öresundsdagen om grundkurser i matematik på universitet och högskolor,
October 31, 2018, Copenhagen, Denmark
 Conference: SYM 10 Years Old,
June 2428, 2019, Copenhagen, Denmark
 Den 16:e Sydostkonferensen i matematik,
August 30, 2019, Karlskrona, Sweden (Gave a talk.)
 The 2nd SNAG meeting,
October 1718, 2019, Karlskrona, Sweden (Gave a talk.)
 Richard Kadison and his mathematical legacy  A memorial conference,
November 2930, 2019, Copenhagen, Denmark
 Den 17:e Sydostkonferensen i matematik,
August 25, 2020, Online
 The 3rd SNAG meeting,
September 2425, 2020, Online
Upcoming...
Other
I am a permanent member of the Swedish Mathematical Society and a member of the Lund
Mathematical Society.
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Last modified: Tuesday, 01st June, 2021 @ 02:27pm (CET)