ResearchResearch paperRetrieval, RAG & Search1 source · Oct 9, 2026

Benchmarking Embedding Geometries and Clustering Algorithms for Unsupervised Patent Claim Classification

This paper asks if an unsupervised representation trained on patent text can recover relevant connections that code-restricted search cannot, and if hyperbolic space helps.

Key points

  • Prior-art retrieval systems are structurally organized around classification codes, making cross-code discovery difficult.
  • We trained a hyperbolic and a matched Euclidean Variational Autoencoder (VAE) on 45,000 US patents (96 runs, 6 seeds).
  • The hyperbolic model agrees less with official classification (NMI 0.2392 vs. 0.3206), which we explain geometrically: the two measures capture different goals, and only one aligns with prior-art search needs.
  • In a study of 10 technology domains (50,000 more patents), we find that a domain's classification breadth--the number of distinct CPC subgroups spanned--predicts approach performance (Pearson r=-0.642, p=0.045, N=10), and that patents per subgroup is an even stronger predictor (r=0.715, p=0.020).

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