Zig Zag symmetry in AdS/CFT duality

The validity of the Bianchi identity, which is intimately connected with the zig zag symmetry, is established, for piecewise continuous contours, in the context of Polakov's gauge field-string connection in the large 'tHooft coupling limit, according to which the chromoelectric `string' propagates in five dimensions with its ends attached on a Wilson loop in four dimensions. An explicit check in the wavy line approximation is presented.Comment: 24 pages version to appear in EPJ