Visualizing Extensions of Argumentation Frameworks as Layered Graphs

TL;DR

This paper introduces a novel 3-layer graph visualization technique for argumentation frameworks that enhances understanding and verification of extensions and semantics, using ILP and heuristic methods for optimized clarity.

Contribution

A new layered graph visualization method for AFs that improves interpretability and verification, with an ILP-based optimization and a scalable heuristic approach.

Findings

Heuristic approach is feasible for large instances.

Heuristic produces at most twice as many crossings as optimal.

Visualization improves exploration and understanding of AF extensions.

Abstract

The visualization of argumentation frameworks (AFs) is crucial for enabling a wide applicability of argumentative tools. However, their visualization is often considered only as an accompanying part of tools for computing semantics and standard graphical representations are used. We introduce a new visualization technique that draws an AF, together with an extension (as part of the input), as a 3-layer graph layout. Our technique supports the user to more easily explore the visualized AF, better understand extensions, and verify algorithms for computing semantics. To optimize the visual clarity and aesthetics of this layout, we propose to minimize edge crossings in our 3-layer drawing. We do so by an exact ILP-based approach, but also propose a fast heuristic pipeline. Via a quantitative evaluation, we show that the heuristic is feasible even for large instances, while producing at most twice as many crossings as an optimal drawing in most cases.