Mathematical Foundations of Polyphonic Music Generation via Structural Inductive Bias
Joonwon Seo
TL;DR
The paper tackles the Missing Middle problem in polyphonic music generation by positing that aligning model structure with the data's intrinsic independence—Pitch and Hand—yields better generalization. It introduces Smart Embedding, a matrix-based factorization that reduces parameters by $48.30\%$ while improving validation loss by $9.47\%$ and achieving a $0.153$-bit bound on information loss, with a $28.09\%$ tighter generalization bound via Rademacher complexity. The approach is underpinned by rigorous proofs using Information Theory, Rademacher Complexity, and Category Theory, and is corroborated by empirical analyses (SVD, effective rank) and an expert listening study with $N=53$, indicating improved texture and hand independence akin to Beethoven. A zero-shot generalization guarantee is established, and a comprehensive human evaluation demonstrates the AI-generated music can be perceptually indistinguishable from authentic Beethoven in many cases, highlighting the practical impact of mathematically grounded AI in creative domains.
Abstract
This monograph introduces a novel approach to polyphonic music generation by addressing the "Missing Middle" problem through structural inductive bias. Focusing on Beethoven's piano sonatas as a case study, we empirically verify the independence of pitch and hand attributes using normalized mutual information (NMI=0.167) and propose the Smart Embedding architecture, achieving a 48.30% reduction in parameters. We provide rigorous mathematical proofs using information theory (negligible loss bounded at 0.153 bits), Rademacher complexity (28.09% tighter generalization bound), and category theory to demonstrate improved stability and generalization. Empirical results show a 9.47% reduction in validation loss, confirmed by SVD analysis and an expert listening study (N=53). This dual theoretical and applied framework bridges gaps in AI music generation, offering verifiable insights for mathematically grounded deep learning.
