Research Papers

Locally isotropic Steinberg groups II. Schur multipliers

E. Yu. Voronetskii

Chebyshev Laboratory, St. Petersburg State University, Department of Mathematics and Mechanics

Abstract: We compute Schur multipliers of locally isotropic Steinberg groups and of all root graded Steinberg groups with root systems of rank at least $ 3 $ (excluding the types $ \mathsf H_3 $ and $ \mathsf H_4 $). As an application, we show that locally isotropic Steinberg groups are well defined as abstract groups.

Keywords: isotropic reductive groups, Steinberg groups, central closedness, Schur multipliers.

Received: 24.09.2025