Gauge-invariant formulation of the d=3 Yang-Mills theory
  We write down the Yang-Mills partition function and the average Wilson loop in terms of local gauge-invariant variables being the six components of the metric tensor of dual space. The Wilson loop becomes the trace of the parallel transporter in curved space, else called the gravitational holonomy. We show that the external coordinates mapping the 3d curved space into a flat 6d space play the role of glueball fields, and there is a natural mechanism for the mass gap generation. 
Dmitri Diakonov (NORDITA and St. Petersburg NPI) and Victor Petrov   (St. Petersburg NPI)