Paraphrase-error decomposition

Defines 'word transformation' via an information-theoretic paraphrase condition (small KL divergence between the context distributions two word sets induce), then algebraically decomposes any embedding-sum residual into named, exactly-quantified error terms (paraphrase error, plus two conditional/unconditional dependence error terms) rather than assuming or spectrally deriving a generative structure for co-occurrence.