TOPOLOGICAL YANG-MILLS COHOMOLOGY IN PURE YANG-MILLS THEORY

Using the first order formalism (BFYM) of the Yang-Mills theory we sho w that it displays an embedded topological sector corresponding to the field content of the Topological Yang-Mills theory (TMW). This pictur e arises after a proper redefinition of the fields of BFYM and gives a clear representation of the non perturbative part of the theory in te rms of the topological sector. In this setting the calculation of the vev of a YM observable is translated into the calculation of a corresp onding (non topological) quantity in TYM, We then compare the topologi cal observables of TYM with a similar set of observables for BFYM and discuss the possibility of describing topological observables in YM th eory. (C) 1998 Elsevier Science B.V. All rights reserved.