On some flat connection associated with locally symmetric surface

摘要

For every two-dimensional manifold M with locally symmetric linear connection ?, endowed also with ?-parallel volume element, we construct a flat connection on some principal fibre bundle P(M,G). Associated with - satisfying some particular conditions - local basis of TM local connection form of such connection is a R(G)-valued 1-form Ω build from the dual basis ω1, ω2 and from local connection form ω of ?. The structural equations of (M, ?) are equivalent to the condition dΩ-ΩΛΩ=0. This work was intended as an attempt to describe in a unified way the construction of similar 1-forms known for constant Gauss curvature surfaces, in particular of that given by R. Sasaki for pseudospherical surface.