  An amplitude analysis of the $\pi^{0}\pi^{0}$ system produced in radiative
$J/\psi$ decays is presented. In particular, a piecewise function that
describes the dynamics of the $\pi^{0}\pi^{0}$ system is determined as a
function of $M_{\pi^{0}\pi^{0}}$ from an analysis of the
$(1.311\pm0.011)\times10^{9}$ $J/\psi$ decays collected by the BESIII detector.
The goal of this analysis is to provide a description of the scalar and tensor
components of the $\pi^0\pi^0$ system while making minimal assumptions about
the properties or number of poles in the amplitude. Such a model-independent
description allows one to integrate these results with other related results
from complementary reactions in the development of phenomenological models,
which can then be used to directly fit experimental data to obtain parameters
of interest. The branching fraction of $J/\psi \to \gamma \pi^{0}\pi^{0}$ is
determined to be $(1.15\pm0.05)\times10^{-3}$, where the uncertainty is
systematic only and the statistical uncertainty is negligible.
