  In our previous paper [Ekren, Touzi and Zhang (2015)], we introduced a notion
of viscosity solutions for fully nonlinear path-dependent PDEs, extending the
semilinear case of Ekren et al. [Ann. Probab. 42 (2014) 204-236], which
satisfies a partial comparison result under standard Lipshitz-type assumptions.
The main result of this paper provides a full, well-posedness result under an
additional assumption, formulated on some partial differential equation,
defined locally by freezing the path. Namely, assuming further that such
path-frozen standard PDEs satisfy the comparison principle and the Perron
approach for existence, we prove that the nonlinear path-dependent PDE has a
unique viscosity solution. Uniqueness is implied by a comparison result.
