https://hellogxp.github.io/tags/representation-similarity/Recent content in Representation-Similarity on Xueping's BlogHugoen-usSat, 20 Jun 2026 00:00:00 +0000https://hellogxp.github.io/posts/cka-delta-universality/Sat, 20 Jun 2026 00:00:00 +0000https://hellogxp.github.io/posts/cka-delta-universality/Different LLM architectures encode high-level concepts in structurally compatible ways—but only up to a point. Geometric similarity between Llama, Qwen, Gemma, and Mistral is moderate at best (CKA_Δ around 0.3–0.7), yet a tiny affine map transfers persona classifiers with 94–99.9% accuracy across six concept domains. This geometric-functional dissociation suggests a weak version of the Platonic Representation Hypothesis: concept representations are universally recoverable, but not universally identical.