Papers and Preprints

1. Linkssymmetrische Algebren und linkssymmetrische Strukturen auf Lie-Algebren,
   Bonner Mathematische Schriften, Vol. 244, 1-65 (1993).


2. Left-symmetric structures on simple modular Lie algebras,
   Journal of Algebra, Vol. 169, Issue 1, 112-138 (1994).


3. Modules for certain Lie algebras of maximal class, with F. Grunewald.
   Journal of Pure and Applied Algebra, Vol. 99, Issue 3, 239-254 (1995).


4. Left-invariant affine structures on reductive Lie groups,
   Journal of Algebra, Vol. 181, Issue 3, 884-902 (1996).


5. Affine structures on nilmanifolds,
   International Journal of Mathematics, Vol. 7, Issue 5, 599-616 (1996).


6. Etale affine representations of Lie groups,
   Geometry and Representation Theory of Real and p-adic Groups,
   Progress in Mathematics, Vol. 158, 35-44 (1998).


7. On a refinement of Ado's theorem,
   Archiv der Mathematik, Vol. 70, Issue 2, 118-127 (1998).


8. Simple left-symmetric algebras with solvable Lie algebra,
   Manuscripta Mathematica, Vol. 95, Issue 3, 397-411 (1998).


9. Degenerations of nilpotent Lie algebras,
   Journal of Lie Theory, Vol. 9, Issue 1, 193-202 (1999).


10. Classification of orbit closures of \(4\)-dimensional complex Lie algebras, with C. Steinhoff.
    Journal of Algebra, Vol. 214, Issue 2, 729-739 (1999).


11. Left-invariant affine structures on nilpotent Lie groups,
    Habilitation, Düsseldorf, 1-83 (1999).


12. Estimates on binomial sums of partition functions,
    Manuscripta mathematica, Vol. 103, Issue 4, 435-446 (2000).


13. Affine cohomology classes for filiform Lie algebras,
    Contemporary Mathematics, Vol. 262, 159-170 (2000).


14. Lie algebra prederivations and strongly nilpotent Lie algebras,
    Communications in Algebra, Vol. 30, Issue 7, 3157-3175 (2002).


15. Sur les dégénérations d'algèbres de Lie,
    Report, 1-10 (2003).


16. Cohomology of groups with applications to number theory,
    1-71, Lecture Notes 2004.


17. Lie-Algebra Kohomologie,
    1-47, Lecture Notes 2005.


18. Degenerations of \(7\)-dimensional nilpotent Lie algebras,
    Communications in Algebra, Vol. 33, Issue 4, 1259-1277 (2005).


19. The Auslander conjecture for NIL-affine crystallographic groups, with K. Dekimpe and S. Deschamps,
    Mathematische Annalen, Vol. 332, Issue 1, 161-176 (2005).


20. On the matrix equation \(XA-AX=X^p\),
    Linear Algebra and its Applications, Vol. 404, Issue 1-3, 147-165 (2005).


21. Characteristically nilpotent Lie algebras and symplectic structures,
    Forum Mathematicum, Vol. 18, Issue 5, 769-787 (2006).


22. Novikov structures on solvable Lie algebras, with K. Dekimpe,
    Journal of Geometry and Physics, Vol. 56, Issue 9, 1837-1855 (2006).


23. A remark on an inequality for the prime counting function,
    Mathematical Inequalities & Applications, Vol. 10, Issue 1, 9-13 (2007).


24. Left-symmetric algebras, or pre-Lie algebras in geometry and physics,
    Central European Journal of Mathematics, Vol. 4, Issue 3, 323-357 (2006).


25. Classical r-matrices and Novikov algebras,
    Geometriae Dedicata, Vol. 122, Issue 1, 145-157 (2006).


26. Degenerations and contractions of Lie algebras and algebraic groups,
    Oberwolfach Reports, Vol. 3, Issue 1, 119-186 (2006).


27. Analytische Zahlentheorie,
    1-109, Lecture Notes 2006.


28. Lie Algebren und Darstellungstheorie,
    1-88, Lecture Notes 2006.


29. Minimal faithful representations of reductive Lie algebras, with W. Moens,
    Archiv der Mathematik, Vol. 89, Issue 6, 513-523 (2007).


30. Cryptography,
    1-75, Lecture Notes 2007.


31. Contractions of Lie algebras and algebraic groups,
    Archivum Mathematicum, Vol. 43, Issue 5, 321-332 (2007).


32. Novikov algebras and Novikov structures on Lie algebras, with K. Dekimpe and K. Vercammen,
    Linear Algebra and its Applications, Vol. 429, Issue 1, 31-41 (2008).


33. Affine actions on nilpotent Lie groups, with K. Dekimpe and S. Deschamps,
    Forum Mathematicum, Vol. 21, Issue 5, 921-934 (2009).


34. LR-algebras, with K. Dekimpe and S. Deschamps,
    New Developments in Lie Theory and Geometry, Amer. Math. Soc., Providence, RI,
    Contemporary Mathematics, Vol. 491, 125-140 (2009).


35. Computing faithful representations for nilpotent Lie algebras, with B. Eick and W. A. de Graaf,
    Journal of Algebra, Vol. 322, Issue 3, 602-612 (2009).


36. Degenerations of pre-Lie algebras, with T. Benes,
    Journal of Mathematical Physics, Vol. 50, Issue 11, 112102, 9 pp. (2009).


37. Commutative Algebra,
    1-87, Lecture Notes 2009.


38. Complete LR-structures on solvable Lie algebras, with K. Dekimpe and K. Vercammen,
    Journal of Group Theory, Vol. 13, Issue 5, 703-719 (2010).


39. Abelian ideals of maximal dimension for solvable Lie algebras, with M. Ceballos,
    Journal of Lie Theory, Vol. 22, Issue 3, 741-756 (2012).


40. Faithful Lie algebra modules and quotients of the universal enveloping algebra, with W. Moens,
    Journal of Algebra, Vol. 325, Issue 1, 440-460 (2011).


41. Affine actions on Lie groups and post-Lie algebra structures, with K. Dekimpe and K. Vercammen,
    Linear Algebra and its Applications, Vol. 437, Issue 5, 1250-1263 (2012).


42. Classification of Novikov algebras, with W. A. de Graaf,
    Applicable Algebra in Engineering, Communication and Computing, Vol. 24, Issue 1, 1-15 (2013).


43. Algebra im Überblick,
    1-87, Lecture Notes 2011.


44. Post-Lie algebra structures and generalized derivations of semisimple Lie algebras, with K. Dekimpe,
    Moscow Mathematical Journal, Vol. 13, Issue 1, 1-18 (2013).


45. Periodic derivations and prederivations of Lie algebras, with W. Moens,
    Journal of Algebra, Vol. 357, 208-221 (2012).


46. Classification of orbit closures in the variety of \(3\)-dimensional Novikov algebras, with T. Benes,
    Journal of Algebra and Its Applications, Vol. 13, Issue 02, 1350081, 33 pp. (2014).


47. Algebraische Zahlentheorie,
    1-113, Lecture Notes 2013.


48. Derived length and nildecomposable Lie algebras,
    Proceedings of the 13th International Symphosium of Mathematics and its Applications 2012,
    Scientific Buletin of the "Politehnica" University of Timisoara, Vol. 58, 15-24 (2013). ISSN 1224-6069.


49. Derivation double Lie algebras,
    Journal of Algebra and Its Applications, Vol. 15, Issue 06, 17 pp. (2016).


50. Jacobi-Jordan algebras, with A. Fialowski,
    Linear Algebra and its Applications, Vol. 459, 586-594 (2014).


51. Post-Lie algebra structures on pairs of Lie algebras, with K. Dekimpe,
    Journal of Algebra, Vol. 464, 226-245 (2016).


52. Commutative post-Lie algebra structures on Lie algebras, with W. A. Moens,
    Journal of Algebra, Vol. 467, 183-201 (2016).


53. Étale representations for reductive algebraic groups with one-dimensional center, with W. Globke,
    Journal of Algebra, Vol. 487, 200-216 (2017).


54. Group Theory,
    1-85, Lecture Notes 2017.


55. Almost inner derivations of Lie algebras, with K. Dekimpe, and B. Verbeke,
    Journal of Algebra and Its Applications, Vol. 17, Issue 11, 26 pp. (2018).


56. Étale representations for reductive algebraic groups with factors \(Sp(n)\) or \(SO(n)\), with W. Globke, and A. Minchenko
    Transformation Groups, Vol. 24, Issue 3, 769-780 (2019).


57. Commutative post-Lie algebra structures and linear equations for nilpotent Lie algebras, with K. Dekimpe, and W. A. Moens,
    Journal of Algebra, Vol. 526, 12-29 (2019).


58. Post-Lie algebra structures for nilpotent Lie algebras, with C. Ender, and W. A. Moens,
    International Journal of Algebra and Computation, Vol. 28, Issue 5, 915-933 (2018).


59. Rota-Baxter operators and post-Lie algebra structures on semisimple Lie algebras, with V. Gubarev,
    Communications in Algebra, Vol. 47, Issue 5, 2280-2296 (2019).


60. Commutative post-Lie algebra structures on Kac-Moody algebras, with P. Zusmanovich,
    Communications in Algebra, Vol. 47, Issue 12, 5218-5226 (2019).


61. Almost inner derivations of Lie algebras II, with K. Dekimpe, and B. Verbeke,
    International Journal of Algebra and Computation, Vol. 31, Issue 02, 341-364 (2021).


62. Algebra I and II,
    1-137, Lecture Notes 2020.


63. Commutative post-Lie algebra structures on nilpotent Lie algebras and Poisson algebras, with C. Ender,
    Linear Algebra and its Applications, Vol. 584, 107-126 (2020).


64. Decompositions of algebras and post-associative algebra structures, with V. Gubarev,
    International Journal of Algebra and Computation, Vol. 30, Issue 3, 451-466 (2020).


65. Crystallographic actions on Lie groups and post-Lie algebra structures,
    Communications of Mathematics, Vol. 29, Issue 01, 67-89 (2021).


66. In memory of Igor Dmitrievich Ado, with V. Gubarev,
    Translation, 1-3 (2019).


67. A Zassenhaus conjecture and CPA-structures on simple modular Lie algebras, with W. A. Moens,
    Journal of Algebra, Vol. 559, 529-546 (2020).


68. Almost inner derivations of 2-step nilpotent Lie algebras of genus 2, with K. Dekimpe, and B. Verbeke,
    Linear Algebra and its Applications, Vol. 608, 185-202 (2021).


69. The structure of Lie algebras admitting a derivation satisfying a polynomial identity, with W. A. Moens,
    Communications in Algebra, Vol. 50, Issue 11, 4636-4647 (2022).


70. Lie algebras and representation theory,
    1-110, Lecture Notes 2021.


71. Algebraic number theory,
    1-97, Lecture Notes 2022.


72. Homological Algebra,
    1-71, Lecture Notes 2022.


73. Rigidity results for Lie algebras admitting a post-Lie algebra structure, with K. Dekimpe and M. Monadjem,
    International Journal of Algebra and Computation, Vol. 32, Issue 08, 1495-1511 (2022).


74. Semisimple decompositions of Lie algebras and prehomogeneous modules, with W. A. Moens,
    Journal of Algebra, Vol. 604, 664-681 (2022).


75. Sympathetic Lie algebras and adjoint cohomology for Lie algebras, with F. Wagemann,
    Journal of Algebra, Vol. 629, 381-398 (2023).


76. Cohomology of Groups and Algebras,
    1-101, Lecture Notes 2023.


77. Counterexamples to the Zassenhaus conjecture on simple modular Lie algebras, with W. A. Moens and P. Páez-Guillán,
    Journal of Algebra, Vol. 629, 21-37 (2023).


78. Post-Lie algebra structures for perfect Lie algebras, with K. Dekimpe and M. Monadjem,
    Communications in Algebra, Vol. 52, Issue 10, 4255-4267 (2024).


79. Characteristically nilpotent Lie groups with flat coadjoint orbits, with J. T. van Velthoven,
    Preprint (2024).