Original Paper: https://arxiv.org/abs/2311.15317

By: Xingtong Yu, Zhenghao Liu, Yuan Fang, Zemin Liu, Sihong Chen, Xinming Zhang

Abstract:

Graph neural networks have emerged as a powerful tool for graph representation learning, but their performance heavily relies on abundant task-specific supervision. To reduce labeling requirement, the "pre-train, prompt" paradigms have become increasingly common. However, existing study of prompting on graphs is limited, lacking a universal treatment to appeal to different downstream tasks. In this paper, we propose GraphPrompt, a novel pre-training and prompting framework on graphs. GraphPrompt not only unifies pre-training and downstream tasks into a common task template but also employs a learnable prompt to assist a downstream task in locating the most relevant knowledge from the pre-trained model in a task-specific manner. To further enhance GraphPrompt in these two stages, we extend it into GraphPrompt+ with two major enhancements. First, we generalize several popular graph pre-training tasks beyond simple link prediction to broaden the compatibility with our task template. Second, we propose a more generalized prompt design that incorporates a series of prompt vectors within every layer of the pre-trained graph encoder, in order to capitalize on the hierarchical information across different layers beyond just the readout layer. Finally, we conduct extensive experiments on five public datasets to evaluate and analyze GraphPrompt and GraphPrompt+.

Summary Notes

Introducing GRAPHPROMPT: A Breakthrough in Graph Analysis

In the digital world, graphs are everywhere, from social networks to recommendation engines, helping us understand complex relationships between vast data points. However, analyzing these graphs to extract meaningful insights is challenging. Conventional methods often rely on extensive labeled datasets, which are hard to keep up-to-date in the rapidly changing digital environment.

This is where the GRAPHPROMPT framework comes in, offering a solution that bridges the gap between initial training and specific analysis tasks, initiating a new phase in graph analysis.

Overcoming Pre-training Challenges in Graph Analysis

Graph Neural Networks (GNNs) have been a game-changer for learning from graphs, especially when supervised data is available. But their effectiveness is limited by a need for large, task-specific datasets.

Pre-training GNNs on unlabeled graphs has been a workaround, but it doesn't fully address the mismatch between pre-training objectives and the needs of specific tasks. The GRAPHPROMPT framework tackles this problem by providing a unified method that combines pre-training with the specific requirements of downstream tasks.

GRAPHPROMPT and Prompt-based Learning

Prompt-based learning has revolutionized how we approach pre-trained models, particularly in language processing.

It uses a specific prompt to adapt a pre-trained model to a new task without extensive retraining. GRAPHPROMPT adopts this strategy for graphs, using a learnable prompt to fine-tune the output layer of a graph encoder.

This ensures the pre-trained model aligns closely with the task at hand, improving performance while reducing the need for large labeled datasets.

How GRAPHPROMPT Works

GRAPHPROMPT employs a two-step process:

• Pre-training Phase: The framework pre-trains a GNN on a task predicting links between subgraphs, which doesn't require labeled data.
• Prompt Tuning Phase: It introduces a learnable prompt that adjusts the final layer of the model, making it more relevant to the specific task, such as classifying nodes or entire graphs, with minimal additional data.

Proving GRAPHPROMPT's Effectiveness

GRAPHPROMPT has been tested across five public datasets on various tasks, where it consistently outperformed existing state-of-the-art methods.

These impressive results demonstrate its versatility and effectiveness in improving task performance with limited supervision, signaling a significant advancement in graph analysis.

The Implications of GRAPHPROMPT

GRAPHPROMPT represents a major step forward, reducing the dependence on large labeled datasets for graph analysis. It is particularly promising for AI engineers in enterprises, offering more efficient, adaptable, and precise analysis capabilities.

Looking forward, the potential for refining and applying GRAPHPROMPT is substantial, promising to reveal new insights from the complex data networks that underpin the digital world.

In summary, GRAPHPROMPT is a testament to the potential of innovative approaches in graph analysis, providing a new way to integrate pre-training with specific analysis tasks through a prompt-based strategy.

As it paves the way for more effective graph analysis, GRAPHPROMPT is set to lead the exploration and discovery in this field, offering AI engineers new tools to decode the complexities of graph data.