Step 1: Filter-response profile
Let $\hat{A} = \tilde{D}^{-1/2}(A+I)\tilde{D}^{-1/2}$ be the symmetrically normalized adjacency.
For node $i$ and channel $f$, collect the signal values at each diffusion order:
$r_{i,f} = \bigl[(\hat{A}^0 X)_{i,f},\; (\hat{A}^1 X)_{i,f},\; \ldots,\; (\hat{A}^L X)_{i,f}\bigr] \in \mathbb{R}^{L+1}$
The profile captures whether the signal is locally stable, smoothed by neighbors, or amplified/attenuated across hops —
independent of semantic content and transferable across graphs.
Step 2: Transformer encoding
Embed each order’s response as a $d$-dimensional token:
$e_{i,f,\ell} = \phi_\text{val}(r_{i,f,\ell}) + p_\ell$
$h_{i,f} = \text{Transformer}([c_\text{cls}, e_{i,f,0}, \ldots, e_{i,f,L}])_{[0]}$
$Z_{i,f} = \phi_\text{out}(h_{i,f})$
Self-attention is applied only among filter-order tokens of the same $(i,f)$ pair,
learning interaction patterns across diffusion orders.