AI RESEARCH
Identified-Set Geometry of Distributional Model Extraction under Top-$K$ Censored API Access
arXiv CS.LG
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ArXi:2605.10407v1 Announce Type: new Modern LLM APIs often reveal only top-$K$ logit scores and censor the remaining vocabulary. We study the per-position distribution-recovery limits of this access model. For censoring threshold $\tau$, the compatible teacher distributions form an identified set whose total-variation diameter is exactly $U_K=(V-K)\exp(\tau)/(Z_A+(V-K)\exp(\tau))$, where $Z_A$ is the observed partition function.