The R-invariance conjecture for tautological equations

Let $\sum_i c_i\Gamma_i=0$ be a tautological equation in codimension $k$ on $\overline{M}_{g,n}$, and let $\mathfrak{r}_l$ be the operators sending decorated graphs on $\overline{M}_{g,n}$ to decorated graphs on $\overline{M}^{\bullet}_{g-1,n+2}$ as defined above. R-invariance conjecture. For all $l$, the equation

$$\mathfrak{r}_l\left(\sum_i c_i\Gamma_i\right)=0$$

holds modulo the tautological equations for pairs $(g',n')$ with $g'<g$, or with $g'=g$ and $n'<n$. These equations are intended to descend from decorated graphs to tautological classes and are related to Gromov--Witten theory; the source notes that a proof is expected in subsequent work.