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Kirchberg-Rordam comparison question: pure infiniteness implies strong pure infiniteness, and weak equals strong for exact C*-algebras

Theorem 1.1: every complex C*-algebra in which every positive element is properly infinite is strongly purely infinite, with an arbitrary cross term in the diagonalization. Theorem 1.2: for exact algebras, proper infiniteness of h⊕nh^{\oplus n} for one fixed nn and all positive hh implies proper infiniteness of every positive element, hence strong pure infiniteness. Corollary: a separable nuclear algebra with this fixed-amplification property absorbs O∞\mathcal O_\infty, with no unitality or simplicity assumption (via Kirchberg's central-sequence results). Not settled: whether weak pure infiniteness implies pure infiniteness for non-exact algebras, which the paper states remains outside its conclusions.

Exact FrontierDelta

Prior state unknown→proved

Scope and record

Occurred: Sep 25, 2026

Delta type: SOURCE CLAIM

Assumptions: VibeMathed verification: lean-checked. Publication: announcement. AI contribution: ai-discovered. 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: Kirchberg-Rordam comparison question: pure infiniteness implies strong pure infiniteness, and weak equals strong for exact C*-algebras · Pure vs strong pure infiniteness

Confidence: Not scored

Registry verification: lean checked · announcement · partial

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Attribution

VibeMathed
registry · event recorded by

Unreleased internal OpenAI model
model · ai model contributor · OpenAI

Artifacts and verifiers

Lean proof (OAI.MainGap.Manuscript.individual_to_strong_main)

lean artifact · pending

Artifact ↗
Lean proof (OAI.WeakPureInfiniteness.exact_weaklyPurelyInfinite_stronglyPurelyInfinite)

lean artifact · pending

Artifact ↗

Compute record

No linked compute attempts recorded.

Lineage and corrections

Lean proof (OAI.WeakPureInfiniteness.exact_weaklyPurelyInfinite_stronglyPurelyInfinite) evidence for this event

Schafhauser-Tikuisis-White, Nuclear C*-algebras: 99 problems (Problem LXXII) evidence for this event

This event attributed to Unreleased internal OpenAI model

Kirchberg-Rordam comparison question: pure infiniteness implies strong pure infiniteness, and weak equals strong for exact C*-algebras evidence for this event

Lean proof (OAI.MainGap.Manuscript.individual_to_strong_main) evidence for this event

VibeMathed record: Kirchberg-Rordam comparison question: pure infiniteness implies strong pure infiniteness, and weak equals strong for exact C*-algebras evidence for this event

Kirchberg-Rordam comparison question: pure infiniteness implies strong pure infiniteness, and weak equals strong for exact C*-algebras parent of this event

Theorem 1.1: every complex C*-algebra in which every positive element is properly infinite is strongly purely infinite, with an arbitrary cross term in the diagonalization. Theorem 1.2: for exact algebras, proper infiniteness of h⊕nh^{\oplus n} for one fixed nn and all positive hh implies proper infiniteness of every positive element, hence strong pure infiniteness. Corollary: a separable nuclear algebra with this fixed-amplification property absorbs O∞\mathcal O_\infty, with no unitality or simplicity assumption (via Kirchberg's central-sequence results). Not settled: whether weak pure infiniteness implies pure infiniteness for non-exact algebras, which the paper states remains outside its conclusions. parent of this event

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