mlsanityData to 7 Oct 2026

On the Interplay of Priors and Overparametrization in Bayesian Neural Network Posteriors

arXiv 2603.22030 ↗First posted 23 Mar 2026cs.LG stat.MLcited by 2

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Abstract (arXiv)

Bayesian neural network (BNN) posteriors are often considered impractical for inference, as symmetries fragment them, non-identifiabilities inflate dimensionality, and weight-space priors are seen as meaningless. In this work, we study how overparametrization and priors together reshape BNN posteriors and derive implications allowing us to better understand their interplay. We show that redundancy introduces three key phenomena that fundamentally reshape the posterior geometry: balancedness, weight reallocation on equal-probability manifolds, and prior conformity. We validate our findings through extensive experiments with posterior sampling budgets that far exceed those of earlier works, and demonstrate how overparametrization induces structured, prior-aligned weight posterior distributions.

Key facts. Cited by 2 papers in the map (data through 7 Oct 2026). Builds on 51 of its 88 references that are in the map. First posted on arXiv 23 Mar 2026.

Builds on

51 of 88 references.

References · 51

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38 more
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