# Semi-Supervised Learning with Competitive Infection Models

## TL;DR

This paper introduces a novel semi-supervised learning method using dynamic infection models for label propagation on graphs, offering an efficient alternative to traditional random walk-based approaches.

## Contribution

It proposes a new label propagation mechanism based on infection dynamics, with theoretical analysis and extensive experiments demonstrating its effectiveness.

## Key findings

- Outperforms traditional methods on multiple benchmarks.
- Provides a scalable and efficient label propagation algorithm.
- Reveals a surprising relation to Laplacian-based approaches.

## Abstract

The goal in semi-supervised learning is to effectively combine labeled and unlabeled data. One way to do this is by encouraging smoothness across edges in a graph whose nodes correspond to input examples. In many graph-based methods, labels can be thought of as propagating over the graph, where the underlying propagation mechanism is based on random walks or on averaging dynamics. While theoretically elegant, these dynamics suffer from several drawbacks which can hurt predictive performance. Our goal in this work is to explore alternative mechanisms for propagating labels. In particular, we propose a method based on dynamic infection processes, where unlabeled nodes can be "infected" with the label of their already infected neighbors. Our algorithm is efficient and scalable, and an analysis of the underlying optimization objective reveals a surprising relation to other Laplacian approaches. We conclude with a thorough set of experiments across multiple benchmarks and various learning settings.