Classification of arithmetic root systems of rank 3

Rank 2 Nichols algebras with finite arithmetic root system

The concept of arithmetic root systems is introduced. It is shown that there is a one-to-one correspondence between arithmetic root systems and Nichols algebras of diagonal type having a finite set of (restricted) Poincare'-Birkhoff-Witt generators. This has strong consequences for both objects. As an application all rank 2 Nichols algebras of diagonal type having a finite set of (restricted) Poincare'-Birkhoff-Witt generators are determined. Key Words: Brandt groupoid, Hopf algebra, pseudo-reflections, Weyl group

Classification of arithmetic root systems

Arithmetic root systems are invariants of Nichols algebras of diagonal type with a certain finiteness property. They can also be considered as generalizations of ordinary root systems with rich structure and many new examples. On the other hand, Nichols algebras are fundamental objects in the construction of quantized enveloping algebras, in the noncommutative differential geometry of quantum groups, and in the classification of pointed Hopf algebras by the lifting method of Andruskiewitsch and Schneider. In the present paper arithmetic root systems are classified in full generality. As a bypr…

正特征下具有有限算术根系的对角型高阶Nichols代数

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

本文分类了正特征域上秩r≥5且具有有限不可约根系的对角型Nichols代数，通过Weyl群胚、算术根系和Cartan图证明其对应于表1中的广义Dynkin图。

Rank 4 finite-dimensional Nichols algebras of diagonal type in positive characteristic

Nichols algebras are fundamental objects in the construction of quantized enveloping algebras and in the classification of pointed Hopf algebras by lifting method of Andruskiewitsch and Schneider. Arithmetic root systems are invariants of Nichols algebras of diagonal type with a certain finiteness property. In the present paper, all rank 4 Nichols algebras of diagonal type with a finite arithmetic root system over fields of arbitrary characteristic are classified. Our proof uses the classification of the finite arithmetic root systems of rank 4.

Root multiplicities for Nichols algebras of diagonal type of rank two

We determine the multiplicities of a class of roots for Nichols algebras of diagonal type of rank two, and identify the corresponding root vectors. Our analysis is based on a precise description of the relations of the Nichols algebra in the corresponding degrees.

Rational Calogero models based on rank-2 root systems: supertraces on the superalgebras of observables

It is shown that the superalgebra of observables of the rational Calogero model based on the root system of I_2(n) type possesses [(n+1)/2] supertraces. Model with three-particle interaction based on the root system G_2 belongs to this class of models and its superalgebra of observables has 3 independent supertraces.