Higher rank Nichols algebras of diagonal type with finite arithmetic root systems in positive characteristic

Abstract: The classification of finite dimensional Nichols algebras of diagonal type plays an important role in the classification of Hopf algebras by the lifting method of N. Andruskiewitsch and H.-J. Schneider over fields of characteristic zero. In this paper, we obtain the classification theorem of all finite-dimensional rank 5, rank 6 and rank 7 Nichols algebras of diagonal type over fields of positive characteristic. Weyl groupoids and finite arithmetic root systems are crucial tools to the classification theorem.