Hypercomplex Transformer: Novel Attention Mechanism

AbstractSelf-attention mechanisms have become foundational across modern deep learning architectures. Recent efforts focus on improving their efficiency, particularly for signal processing tasks. The existing approaches employ complex-valued representations for inputs and weights and achieve higher accuracy at the cost of increased model size and inference latency. Dual-numbered algebra offers a promising alternative that allows efficient multiplication and faster inference with the same representational capacity. Inspired by previous studies in the field of hypercomplex neural networks, we introduce a generalized hypercomplex attention block and integrate it into Transformer-based models for EEG classification. Our experiments include adaptation of the hypercomplex models, so that the number of parameters is equal to that of their real-valued counterparts. Across all scenarios, the dual- and complex-numbered models consistently outperform the real ones, demonstrating superior accuracy. This work presents hypercomplex attention as a competitive and computationally efficient strategy with potential value to solve multiple NLP tasks.