Khalef Yaddaden

I am a JSPS Postdoctoral Research fellow in the Graduate School of Mathematics of Nagoya University (Japan) under Professor Hidekazu Furusho.

I did my Ph.D. in mathematics at the University of Strasbourg (France) under the supervision of Professor Benjamin Enriquez.

I am interested in various aspects of multiple zeta values, their cyclotomic analogues the multiple polylogarithm values at roots of unity and their connections to associators and Grothendieck-Teïchmuller theory.

Upcoming events

Mar 05, 2025	Invited speaker for the Colloque tournant du RT algèbre at University of Clermont Auvergne, Clermont-Ferrand, France.
Mar 14, 2025	Invited speaker for the Algebraic and Combinatorial Perspectives in the Mathematical Sciences online seminar.
Jul 12, 2025	Invited speaker for the 4nd International Workshop on Multiple Zeta Values and Related Fields at Tongji University, Shanghai, China.
Sep 14, 2025	Invited speaker for the Around associators: from integrable systems to number theory conference at Les Diablerets, Switzerland.

Selected publications

The cyclotomic double shuffle torsor in terms of Betti and de Rham coproducts

Khalef Yaddaden

Journal of Pure and Applied Algebra, 2024

Abs Bib PDF

We prove a cyclotomic generalization of Enriquez and Furusho’s result stating that the scheme of double shuffle and regularization relations between multiple zeta values arising from Racinet’s formalism is a torsor of isomorphisms between “Betti” and “de Rham” objects. After reviewing the “de Rham” objects arising from a crossed product interpretation of Racinet’s formalism, we construct the “Betti” objects based on an orbifold fundamental group. We then show that the scheme of double shuffle and regularization relations is a subtorsor of stabilizer schemes relating “Betti” and “de Rham” coproducts.
@article{yad2, title = {The cyclotomic double shuffle torsor in terms of Betti and de Rham coproducts}, author = {Yaddaden, Khalef}, journal = {Journal of Pure and Applied Algebra}, volume = {228}, number = {5}, pages = {107550}, year = {2024}, issn = {0022-4049}, doi = {https://doi.org/10.1016/j.jpaa.2023.107550}, url = {https://www.sciencedirect.com/science/article/pii/S0022404923002323}, }