  We present a procedure to map the constitutive laws of elasticity (both in
the linear and nonlinear regime) onto a discrete atomic lattice and we apply
the resulting elastic lattice model to investigate the strain field within an
embedded nano-inhomogeneity. We prove that its elastic behavior at the
nanoscale is governed by relevant atomistic effects. In particular, we
demonstrate that such effects on the linear and nonlinear elastic properties
are described by the same scaling exponent, in a large range of elastic
contrast between the matrix and the nano-inhomogeneity. This suggests that the
linear and nonlinear elastic behaviors of the composite system belong to the
same universality class (at least within the nanometer length scale here
investigated).
