Ultrametric OGP - parametric RDT \emph{symmetric} binary perceptron connection

arXiv cs.LG / 4/22/2026

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Key Points

  • The paper extends the framework of parametric RDT to connect it with overlap gap properties (OGPs) in the solution space geometry of symmetric binary perceptrons (SBPs).
  • It introduces s-level ultrametric OGPs and derives rigorous upper bounds on the corresponding constraint densities using an analytical union-bounding program with combinatorial and probabilistic components.
  • Numerical evaluations show the tightest bounds at low ultrametric levels, with \(\bar{\alpha}_{ult_1} \approx 1.6578\) and \(\bar{\alpha}_{ult_2} \approx 1.6219\), closely matching parametric RDT estimates at lifting levels 3 and 4.
  • The authors report strong agreement not only on these thresholds but also on overlap values and the relative sizes of ultrametric clusters across multiple parameters.
  • They propose conjectures relating the limiting ultrametric OGP thresholds to both algorithmic thresholds and the infinite-lifting limit of parametric RDT, and discuss the possibility of a full isomorphism between the two descriptions.

Abstract

In [97,99,100], an fl-RDT framework is introduced to characterize \emph{statistical computational gaps} (SCGs). Studying \emph{symmetric binary perceptrons} (SBPs), [100] obtained an \emph{algorithmic} threshold estimate \alpha_a\approx \alpha_c^{(7)}\approx 1.6093 at the 7th lifting level (for \kappa=1 margin), closely approaching 1.58 local entropy (LE) prediction [18]. In this paper, we further connect parametric RDT to overlap gap properties (OGPs), another key geometric feature of the solution space. Specifically, for any positive integer s, we consider s-level ultrametric OGPs (ult_s-OGPs) and rigorously upper-bound the associated constraint densities \alpha_{ult_s}. To achieve this, we develop an analytical union-bounding program consisting of combinatorial and probabilistic components. By casting the combinatorial part as a convex problem and the probabilistic part as a nested integration, we conduct numerical evaluations and obtain that the tightest bounds at the first two levels, \bar{\alpha}_{ult_1} \approx 1.6578 and \bar{\alpha}_{ult_2} \approx 1.6219, closely approach the 3rd and 4th lifting level parametric RDT estimates, \alpha_c^{(3)} \approx 1.6576 and \alpha_c^{(4)} \approx 1.6218. We also observe excellent agreement across other key parameters, including overlap values and the relative sizes of ultrametric clusters. Based on these observations, we propose several conjectures linking ult-OGP and parametric RDT. Specifically, we conjecture that algorithmic threshold \alpha_a=\lim_{s\rightarrow\infty} \alpha_{ult_s} = \lim_{s\rightarrow\infty} \bar{\alpha}{ult_s} = \lim_{r\rightarrow\infty} \alpha_{c}^{(r)}, and \alpha_{ult_s} \leq \alpha_{c}^{(s+2)} (with possible equality for some (maybe even all) s). Finally, we discuss the potential existence of a full isomorphism connecting all key parameters of ult-OGP and parametric RDT.