Counterexample to majority optimality in NICD with erasures

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ivanisvili, Paata, Xie, Xinyuan
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911227855241216
author Ivanisvili, Paata
Xie, Xinyuan
author_facet Ivanisvili, Paata
Xie, Xinyuan
contents We asked GPT-5 Pro to look for counterexamples among a public list of open problems (the Simons ``Real Analysis in Computer Science'' collection). After several numerical experiments, it suggested a counterexample for the Non-Interactive Correlation Distillation (NICD) with erasures question: namely, a Boolean function on 5 bits that achieves a strictly larger value of $\mathbb{E}|f(z)|$ than the 5-bit majority function when the erasure parameter is $p=0.40.$ In this very short note we record the finding, state the problem precisely, give the explicit function, and verify the computation step by step by hand so that it can be checked without a computer. In addition, we show that for each fixed odd $n$ the majority is optimal (among unbiased Boolean functions) in a neighborhood of $p=0$. We view this as a little spark of an AI contribution in Theoretical Computer Science: while modern Large Language Models (LLMs) often assist with literature and numerics, here a concrete finite counterexample emerged.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20013
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Counterexample to majority optimality in NICD with erasures
Ivanisvili, Paata
Xie, Xinyuan
Probability
Computational Complexity
Information Theory
Combinatorics
68Q87, 94A15, 06E30
We asked GPT-5 Pro to look for counterexamples among a public list of open problems (the Simons ``Real Analysis in Computer Science'' collection). After several numerical experiments, it suggested a counterexample for the Non-Interactive Correlation Distillation (NICD) with erasures question: namely, a Boolean function on 5 bits that achieves a strictly larger value of $\mathbb{E}|f(z)|$ than the 5-bit majority function when the erasure parameter is $p=0.40.$ In this very short note we record the finding, state the problem precisely, give the explicit function, and verify the computation step by step by hand so that it can be checked without a computer. In addition, we show that for each fixed odd $n$ the majority is optimal (among unbiased Boolean functions) in a neighborhood of $p=0$. We view this as a little spark of an AI contribution in Theoretical Computer Science: while modern Large Language Models (LLMs) often assist with literature and numerics, here a concrete finite counterexample emerged.
title Counterexample to majority optimality in NICD with erasures
topic Probability
Computational Complexity
Information Theory
Combinatorics
68Q87, 94A15, 06E30
url https://arxiv.org/abs/2510.20013