Graph Hierarchical Recurrence for Long-Range Generalization

Stefano Carotti, Marco Pacini, Alessio Gravina, Davide Bacciu, Bruno Lepri, Sebastiano Bontorin

Main figure for Graph Hierarchical Recurrence for Long-Range Generalization

Abstract

Graph Neural Networks (GNNs) and Graph Transformers (GTs) are now a fundamental paradigm for graph learning, combining the representation-learning capabilities of deep models with the sample efficiency induced by their inductive biases. Despite their effectiveness, a large body of work has shown that these models still face fundamental limitations in tasks that require capturing correlations between distant regions of a graph. To address this issue, we introduce Graph Hierarchical Recurrence (GHR), a novel framework that operates jointly on the input graph and on a hierarchical abstraction obtained through pooling. We also show that the limitations of existing models are even more pronounced in out-of-range generalization, where test instances involve interactions over distances longer than those observed during training. By contrast, despite its simple design, GHR provides three key advantages: strong performance on long-range dependencies, improved out-of-range generalization, and high parameter efficiency. To corroborate these claims, we show that across a broad set of long-range benchmarks, GHR consistently outperforms existing graph models while using as little as 1% of the parameters of current state-of-the-art models. These results suggest a complementary direction to the current trend of scaling architectures to obtain graph foundation models, indicating that increased model capacity alone may not be sufficient for generalization.

Proposed method: GHR

Benchmark Results

Tested on 2 datasets

Tables show presented results in global context (best 3 papers + GCN + MLP).

ECHO Benchmark

#ModelMAE ↓Paper
1
GHR
0.0350 ±0.0040
This paper
2
GRIT
0.1210 ±0.0130
This paper
3
GHR-GINE
0.3790 ±0.1910
This paper
4
GPS
0.4720 ±0.0500
This paper
5
SWAN
0.8960 ±0.2320
This paper
6
A-DGN
1.1510 ±0.0380
This paper
7
DRew
1.2430 ±0.0470
This paper
8
PH-DGN
1.3230 ±0.4850
This paper
9
GIN/GINE
1.6300 ±0.1610
This paper
10
GIN
1.6300 ±0.1610
11
GCNII
2.0050 ±0.0930
This paper
12
GCN
2.1020 ±0.0940
This paper
13
GraphCON
2.9690 ±0.1890
This paper

LRIM Graph Benchmark

#Modellog-MSE ↓Paper
1
GPS-RWSE
-4.3450 ±0.0650
2
GPS-Base
actual #2 vs paper #4 2 places worse
-4.3400 ±0.1010
best reported
actual #2 vs paper #4 2 places worse
paper -4.2110 ±0.1550

Difference within reported uncertainty; not counted as underperformance.

paper -4.2110 ±0.1550 Δ at pub 0.1290
3
GPS-LapPE
actual #3 vs paper #3
-4.3340 ±0.0650
actual #3 vs paper #3
paper -4.3340 ±0.0650

Improvement within reported uncertainty; not highlighted.

paper -4.3340 ±0.0650 Δ at pub 0.0860
5
GHR-GatedGCN
-4.1950 ±0.0610
This paper
6
GatedGCN
-3.9190 ±0.2230
8
GIN
-2.4060 ±0.1480
SOTA performance (not significantly different from the best) Proposed method (this paper) Baseline / comparison (this paper) Global context (other papers)