Stable Phase Retrieval for Spans of Independent Random Variables

Pedro Abdalla, Jaume de Dios Pont, João P. G. Ramos, Mitchell A. Taylor

Theorem 6.1 gives an explicit quantitative stable-phase-retrieval bound for the closed real L² span of independent centred normalized random variables under indexed two-sided L¹ bounds on all but at most one coordinate. Its proof uses a head–tail concentration versus diffusion argument and Sperner-type anticoncentration.

Sources for this record

What was already known

Earlier work covered a disjoint-indicator model or sufficiency under finite fourth moments and identical distributions. The human authors first proved the full qualitative characterization by a different compactness argument.

AI involvement AI-centered

LLMs generated the quantitative combinatorial strategy after guidance and access to the authors’ original proof. Abdalla, de Dios Pont, Ramos and Taylor rewrote it and reviewed the formal statements.

The source identifies a model-generated quantitative combinatorial strategy but says it depended on the authors' prior proof and substantial guidance.

Importance Notable

The alternative proof gives explicit stability bounds without those earlier distribution and moment restrictions.

Limitations

The Lean verification is reported for the quantitative Theorem 6.1 under its indexed hypotheses. It does not transfer AI credit to the authors’ earlier qualitative proof.

Technical verification Formal (Lean 4)

The authors report Lean 4 verification of the quantitative statement in Theorem 6.1 and identify showcase.lean as its direct translation. The machine check is source-reported; independent checking of statements is not counted as human proof checking.

Formal checking

Lean kernel checking of showcase.lean and the QuantitativePR proof

Checker
Lean 4 using the authors' RandomVarSPR formalization
Scope
Theorem 6.1 quantitative real L2 stable-phase-retrieval bound under independent, centred, normalized variables and indexed L1 bounds
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

The authors explain the head–tail decomposition, concentrated and diffuse branches, and anticoncentration mechanism, with a separate human compactness proof of the same theorem.

Correction and publication history

2026-10-18 · publication

The alternative proof gives explicit stability bounds without those earlier distribution and moment restrictions.

Read this published revision