SYNTRA turned a handful of retrieval examples into training data, and beat human calibration on four of six tasks
AspireAI community · arXiv
Adapting an embedding model to a new domain normally means designing a training set by hand, which is the expensive part. SYNTRA inverts the order: given an unlabelled corpus and a few relevant query-document pairs, it infers the implicit information needs and relevance criteria, then uses feedback on trial outputs to refine its own instructions for query generation and relevance assessment. The result is a self-improving synthesis loop rather than a one-shot data dump. Across 24 datasets spanning 15 domains, the same workflow produced effective training data, and it helped even strong embedding models that already had labelled training sets. On six evaluated tasks the self-improvement strengthened supervision everywhere, giving better retrieval than human calibration on four of them, and the training value held across a 32-fold range of synthetic data sizes on MS MARCO. The limitation is that this is about embedding models specifically, and the paper measures retrieval quality rather than downstream task performance in a full RAG stack.
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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.