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The Inverse Generator Problem on Hilbert Spaces

One finite-dimensional construction settles several related questions. Besides the inverse generator problem, it gives a generator whose Cayley transforms satisfy the ordinary Kreiss resolvent condition but are neither strongly Kreiss bounded nor power bounded, and it shows the Crank-Nicolson scheme is unstable in operator norm both over long times at fixed step size and under mesh refinement at fixed final time. Version 2 adds Theorem 1.4, whose part (i) solves Question 6.1 of Chalmoukis, Tsikalas and Yakubovich; that question is tracked as its own entry.

Exact FrontierDelta

disproved→disproved

Scope and record

Occurred: Oct 29, 2026

Delta type: REGISTRY REVISION

Assumptions: VibeMathed verification: unreviewed. Publication: preprint. AI contribution: ai-assisted. VibeMathed editorial classifications, scores, notes, relations, and dataset structure are CC BY 4.0. Source statements and linked content retain their own rights.

Canonical aliases: The Inverse Generator Problem on Hilbert Spaces · Inverse generator problem

Confidence: Not scored

Registry verification: unreviewed · preprint · resolved

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Attribution

VibeMathed
registry · event recorded by

Martin Meyries
human · human collaborator

Mark Veraar
human · human collaborator

Emiel Lorist
human · human collaborator

ChatGPT 5.6 Pro
model · ai model contributor · OpenAI

Claude Fable
model · ai model contributor · Anthropic

Artifacts and verifiers

Lean 4 formalization repository

lean artifact · pending

Artifact ↗

Compute record

No linked compute attempts recorded.

Lineage and corrections

Corrects The Inverse Generator Problem on Hilbert Spaces →

Supersedes The Inverse Generator Problem on Hilbert Spaces →

Separation Between the Ordinary and Strong Kreiss Constants evidence for this event

The Inverse Generator Problem on Hilbert Spaces parent of this event

VibeMathed record: The Inverse Generator Problem on Hilbert Spaces evidence for this event

This event attributed to Martin Meyries

This event attributed to ChatGPT 5.6 Pro

This event attributed to Mark Veraar

This event attributed to Claude Fable

Lean 4 formalization repository evidence for this event

This event attributed to Emiel Lorist

One finite-dimensional construction settles several related questions. Besides the inverse generator problem, it gives a generator whose Cayley transforms satisfy the ordinary Kreiss resolvent condition but are neither strongly Kreiss bounded nor power bounded, and it shows the Crank-Nicolson scheme is unstable in operator norm both over long times at fixed step size and under mesh refinement at fixed final time. Version 2 adds Theorem 1.4, whose part (i) solves Question 6.1 of Chalmoukis, Tsikalas and Yakubovich; that question is tracked as its own entry. parent of this event

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The Inverse Generator Problem on Hilbert Spaces — Mathematical Frontier Network