Absolute parallelism for 2-nondegenerate CR structures via bigraded Tanaka prolongation
Absolute parallelism for 2-nondegenerate CR structures via bigraded Tanaka prolongation
Abstract This article is devoted to the local geometry of everywhere 2-nondegenerate CR manifolds M of hypersurface type. An absolute parallelism for such structures was recently constructed independently by Isaev and Zaitsev, Medori and Spiro, and Pocchiola in the minimal possible dimension ( <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mrow> <m:mrow> <m:mo>dim</m:mo> <m:mo></m:mo> <m:mi>M</m:mi> …