  A mechanism of generating the metric is proposed, where the Kalb-Ramond
symmetry existing in the topological BF theory is broken through the
condensation of the string fields which are so introduced as to couple with the
anti-symmetric tensor fields $B$, invariantly under the Kalb-Ramond symmetry.
In the chiral decomposition of the local Lorentz group, the non-Abelian $B$
fields need to be generalized to the string fields. The mechanism of the
condensation is discussed, viewing the confinement problem and the polymer
physics.
