Structure functions are obstructions to integrability of G-structures, where G is a Lie group,

on a real or complex manifold. These well known invariants are expressed in terms of Spencer

cohomology of the corresponding graded Lie algebra. Many important particular cases of structure

functions are known under the names of Riemann tensor, Nijenhuis tensor, etc.

... more

on a real or complex manifold. These well known invariants are expressed in terms of Spencer

cohomology of the corresponding graded Lie algebra. Many important particular cases of structure

functions are known under the names of Riemann tensor, Nijenhuis tensor, etc.

... more