Spectral dimension of elastic Sierpinski gaskets

The spectral dimension of an elastic Sierpinski gasket with nearest-neighbor central forces has been found to be $\tilde{d}=\frac{2\ln 3}{\ln 6}$, which is different from $\tilde{d}=\frac{2\ln 3}{\ln 5}$ for the isotropic force model. This result lends support to the argument that the two force models belong to two distinct universality classes.