ESR 5:
Ergys Çokaj

My name is Ergys Çokaj and I come from Albania. I have completed my Bachelor and Master Degree in Mathematics and Applications at the University of Camerino in Italy.
Thanks to the study program I chose, I have gained a substantial knowledge base in pure  mathematics and also in the applications of mathematics. During the academic years I have studied the fundamental bases of Numerical Analysis, Calculus, Algebra and Geometry and then learned to illustrate their wide applications to other related fields.
I have spent more than five years of studying in Italy and I do profoundly attest that I have had the chance to work and cooperate with very well prepared professors and colleagues from fascinating scientific backgrounds. This experience made me keen to enter in the vast world of mathematics.

I applied for the ESR5 position in the THREAD project because I see it as an extension of my study interests and I consider my background strongly related to the prerequisites for the project.
An exciting fact about THREAD is the direct opportunity to collaborate with researchers with different backgrounds, from all around the world. THREAD also provides us with advanced research trainings, transferable skills trainings and industrial workshops, which contribute on enriching our background as future scientists.
I am enormously grateful for this given opportunity. My vivid qualities depend on honesty, consistency and zeal, always determined to perform the required tasks in a fruitful manner.
I am convinced that the experience of working on THREAD will strengthen my skills, increase my knowledge and change the way I see the world around me.

To know more about my career and research, check the following links: ResearchGate, GitHub and LinkedIn.

Host Institution
Norwegian University of Science and Technology (Norway)


Study implementation issues for Lie group integrators and invariant preserving integrators. Results will include: 1) Variable step size Lie group integrators with error control; 2) Invariant preserving schemes for mechanical systems evolving on Riemannian manifolds; 3) Model reduction applied to large dynamical systems on Lie groups and manifolds.

Expected Results

New software generation for Lie group integration to be used for concrete applications from THREAD. For Lie group integrators with stepwise updated local coordinates standard error control from integrators on linear spaces can be applied. There is no such direct reference to coordinate charts for composition based Lie group integrators making them more tricky to work with (order conditions for non-commutative spaces). As for integral preserving schemes the use of retractions will be essential, in particular efficient maps based on geodesics. For large dynamical systems on manifolds the methodology for reducing the dimension will follow ideas from shape analysis, collaboration with ESR4 is natural.


Articles in peer-reviewed scientific journals

  • Martin Arnold, Elena Celledoni, Ergys Çokaj, Brynjulf Owren, Denise Tumiotto (2024): B-stability of numerical integrators on Riemannian manifolds; Journal of Computational Dynamics 11, 92–107; DOI: 10.3934/jcd.2024002, see also link
  • Elena Celledoni, Ergys Çokaj, Andrea Leone, Davide Murari, Brynjulf Owren (2022): Lie group integrators for mechanical systems; International Journal of Computer Mathematics 99(1), 58–88; DOI: 10.1080/00207160.2021.1966772, see also link

Publications in conference proceedings

  • Elena Celledoni, Ergys Çokaj, Andrea Leone, Davide Murari, Brynjulf Owren (2022): Dynamics of the N-fold Pendulum in the Framework of Lie Group Integrators. In: Matthias Ehrhardt, Michael Günther (eds.): Progress in Industrial Mathematics at ECMI 2021. Mathematics in Industry, vol 39. Springer Cham, pp. 297–304; DOI: 10.1007/978-3-031-11818-0_39, see also link