lean artifact · pending
Artifact ↗Williams's one-tape question: simulating one-tape time in space
Theorem 1.1: for a fixed deterministic machine with one writable tape and head (and finitely many read-only input heads), the finite-control and halting outcome by time can be computed in work-space bits given the cap ; without a supplied cap, a machine halting at time is simulated in space. Hence for every . Simulation time is unrestricted, the final tape is not materialized, no lower bound or optimality is claimed, and for several writable tapes only is given.
Exact FrontierDelta
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: Williams's one-tape question: simulating one-tape time $T$ in $O(T^{1/2-\delta})$ space · One-tape time in sub-square-root space
Confidence: Not scored
Registry verification: lean checked · announcement · candidate
Attribution
VibeMathed
registry · event recorded by
Unreleased internal OpenAI model
model · ai model contributor · OpenAI
Artifacts and verifiers
Compute record
No linked compute attempts recorded.
Lineage and corrections
This event attributed to Unreleased internal OpenAI model
Theorem 1.1: for a fixed deterministic machine with one writable tape and head (and finitely many read-only input heads), the finite-control and halting outcome by time can be computed in work-space bits given the cap ; without a supplied cap, a machine halting at time is simulated in space. Hence for every . Simulation time is unrestricted, the final tape is not materialized, no lower bound or optimality is claimed, and for several writable tapes only is given. parent of this event
Lean Comparator challenge OneTapeSpace (OpenAI math release) evidence for this event
Williams, Simulating Time with Square-Root Space (full version, Section 5) evidence for this event
Williams's one-tape question: simulating one-tape time in space parent of this event
VibeMathed record: Williams's one-tape question: simulating one-tape time in space evidence for this event
Williams's one-tape question: simulating one-tape time in space evidence for this event
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