Let
$\overline {\mathcal {M}}_{g, m|n}$
denote Hassett’s moduli space of weighted pointed stable curves of genus g for the heavy/light weight data
$$\begin{align*}\left(1^{(m)}, 1/n^{(n)}\right),\end{align*}$$
and let
$\mathcal {M}_{g, m|n} \subset \overline {\mathcal {M}}_{g, m|n}$
be the locus parameterizing smooth, not necessarily distinctly marked curves. We give a change-of-variables formula which computes the generating function for
$(S_m\times S_n)$
-equivariant Hodge–Deligne polynomials of these spaces in terms of the generating functions for
$S_{n}$
-equivariant Hodge–Deligne polynomials of
$\overline {\mathcal {M}}_{g,n}$
and
$\mathcal {M}_{g,n}$
.