Predictive Coding Graphs are a Superset of Feedforward Neural Networks

Predictive coding graphs (PCGs) are a recently introduced generalization to predictive coding networks (PCNs), a neuroscience-inspired probabilistic latent variable model. Here, we prove how PCGs define a mathematical superset of feedforward artificial neural networks (multilayer perceptrons). This positions PCNs more strongly within contemporary machine learning, and reinforces earlier proposals to study the use of non-hierarchical neural networks for learning tasks, and more generally the notion of topology in neural networks.