A co-trained LLM judge turned reference answers alone into a usable reward, matching direct RLVR on verifiable tasks and producing NIH grant abstracts that scientists found harder to distinguish from real ones
AspireAI community · arXiv
In many post-training settings the good answers are recognizable but hard to score with an explicit reward, and reinforcement learning with verifiable rewards only applies where a correctness signal exists. This paper asks whether a co-trained LLM judge can use reference answers alone as the sole reward for on-policy post-training of reasoning models, calling the method Reinforced Adversarial Learning. Validated on three verifiable tasks including integer multiplication, code-based arithmetic-expression synthesis and SMILES-to-formula translation, where the verifiers are used only for evaluation, RAL matches direct RLVR given sufficiently capable judges and enough training. Applied to scientific abstract generation it guides the generator toward the domain of the reference abstracts even when the prompt leaves that domain unspecified, and for NIH grant proposals conditioned on the title, human scientists and an ensemble of LLM judges found the generations harder to distinguish from real abstracts than frontier-LLM baselines. The limitation is that reward quality is bounded by the judge, so the approach needs a judge at least as strong as the domain is hard.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.