what-does-a-discrete-diffusion-model-learn--9a91f4ab·1 events·first seen Aliases: What Does a Discrete Diffusion Model Learn?
A new arXiv preprint provides a rigorous theoretical framework for understanding what discrete diffusion models learn, proving the 'Oracle Distance' theorem: the negative ELBO exactly equals data entropy plus the path KL from the oracle reverse process to the learned one. The work shows that denoiser, score ratio, and bridge plug-in parameterizations are the same object in different coordinates, with closed-form conversions among them. It unifies several existing discrete diffusion losses (MDM, UDM, SEDD, GIDD) as special cases and identifies practical consequences, such as why denoiser parameterization causes the uniform ELBO to diverge at initialization. All identities are verified numerically on an exactly solvable model.