Monte Carlo to Las Vegas for Recursively Composed Functions
- URL: http://arxiv.org/abs/2601.08073v1
- Date: Mon, 12 Jan 2026 23:34:37 GMT
- Title: Monte Carlo to Las Vegas for Recursively Composed Functions
- Authors: Bandar Al-Dhalaan, Shalev Ben-David,
- Abstract summary: We study the composition limits of general measures in query complexity.<n>We show this limit converges under reasonable assumptions about the measure.<n>We then give a surprising result regarding the composition limit of randomized query complexity.
- Score: 0.26709266817192023
- License: http://creativecommons.org/licenses/by-sa/4.0/
- Abstract: For a (possibly partial) Boolean function $f\colon\{0,1\}^n\to\{0,1\}$ as well as a query complexity measure $M$ which maps Boolean functions to real numbers, define the composition limit of $M$ on $f$ by $M^*(f)=\lim_{k\to\infty} M(f^k)^{1/k}$. We study the composition limits of general measures in query complexity. We show this limit converges under reasonable assumptions about the measure. We then give a surprising result regarding the composition limit of randomized query complexity: we show $R_0^*(f)=\max\{R^*(f),C^*(f)\}$. Among other things, this implies that any bounded-error randomized algorithm for recursive 3-majority can be turned into a zero-error randomized algorithm for the same task. Our result extends also to quantum algorithms: on recursively composed functions, a bounded-error quantum algorithm can be converted into a quantum algorithm that finds a certificate with high probability. Along the way, we prove various combinatorial properties of measures and composition limits.
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