Reachability LabsUnderstand what remains possible.
Research and evidence

Research you can inspect and build on.

Find the papers, software, data archives, benchmark results, and downloadable records behind the site's claims.

The central question is simple: after a process has committed to a particular history, what futures are still available from its current state?

Three settings, three different kinds of conclusion.

All three ask the same kind of question: given the current state and target, what outcomes remain possible? The strength of the answer differs in each setting.

StudyWhat was measuredMain resultWhat it does not establish
Random 3-SATWhether satisfying completions remain from exact committed prefixes, checked with a solver oracle.A sharp constructive-accessibility boundary appears well before the ordinary existence threshold; tested jam prefixes in the bridge region were residual UNSAT.A universal law for all search processes or problem families.
AI reasoningRepeated continuations from exact token prefixes in Qwen2.5-Math-7B-Instruct on a floor-sum problem family.Correct and wrong source traces separate in measured target reach; targeted edits test whether access can reopen.Logical impossibility, hidden-state access, or portability to other models, tasks, or sampling policies.
Graph coloringA second oracle-backed constraint problem under its own process and target rules.A similar process-versus-landscape split appears with a different surface pattern.General cross-domain portability, an identical mechanism, or universal timing.

Measure the answer field from the exact point reasoning has reached.

What the study did

At selected points in a reasoning trace, the study generated many continuations from exactly that prefix and measured which answers they produced. It compared correct and incorrect source traces, localized changes in token coordinates, and tested whether small corrective edits could reopen measured access to the target.

Published configuration: Qwen2.5-Math-7B-Instruct · floor-sum task family · paper and evidence archive v1.1-RC18 · July 2026. Across 18 localized wrong-source traces, the median onset bracket was 4.5 tokens; the final wrong answer appeared a median 170 tokens after observed target reach crossed the declared dead threshold.
Where the claim stops: “Dead” is an instrument-relative label under the declared model, prefix, sampler, budget, extraction rule, validity gate, and target definition. It is not a proof that no recovery is possible under different conditions. ReachScan v0.3.5 also requires token-level prefix access; closed hosted APIs and hidden reasoning need new adapters.

Random 3-SAT makes the route-versus-landscape distinction exact.

Main result

At n = 1,000, the measured constructive-accessibility crossover is αcross = 1.5352, with a 95% bootstrap interval of [1.526, 1.555]. A finite-asymptote fit using n ≤ 700 predicted approximately 1.541—within 0.006 of the later large-n result.

In the bridge region, 194 of 194 tested jam prefixes were residual UNSAT, with no timeouts. The solver oracle establishes that those exact committed prefixes had no satisfying completion even though the underlying random instances remained in a regime where solutions generally exist.

Where the claim stops: this is a result for the declared random 3-SAT ensemble, process, solver checks, and protocol. It does not establish the same boundary in engineering organizations or every constructive process.

Interactive benchmark: change system size and inspect the measured separation between process success and the existence-side reference.

Graph coloring: a second exact test

A second constraint problem shows a similar separation between whether a solution exists and whether the tested process can still reach one. This is early evidence that the question can be studied outside SAT; it does not prove broad portability or a common mechanism.

From computational research to engineering practice.

Evaluate the worksheets in real work

The worksheets are available for real-world evaluation. We are looking for cases that show whether they uncover a missed option, prevent a wasted test or difficult-to-reverse change, improve a handoff—or merely add paperwork.

No outside case series has yet shown that they improve decisions beyond competent existing practice.

Open the primary record for each artifact.

Versions belong to individual artifacts. The AI paper, software, technical report, SAT predecessor work, website primer, and engineering worksheets do not share one version number.

ItemVersionStatusPrimary recordAdditional files
AI core articlev1.1-RC18PublishedConcept DOIVersion DOI
AI evidence archivev1.1-RC18PublishedConcept DOIVersion DOI
Full Technical Reportv0.14.0Published July 9, 2026Zenodo record86 pages
ReachScan softwarev0.3.5Public releaseGitHub repositoryZenodo software record
3-SAT paper and supplementv1.0PublicOSFZenodo publication record
SAT code demov0.3.2Public source-code releaseGitHub releaseRepository
The Builder's Viewv4.0Public primerPDFAudio
Engineering worksheetsv0.2Free worksheetsWorksheet pageFillable PDF and JSON files

Verify a downloaded file

Choose a file and its expected artifact. Your browser computes SHA-256 locally; the file is not uploaded.

Inspect the process, not just its endpoint.

These interactives have different jobs. The explanations illustrate a distinction; the benchmark shows measured results; the trace visualizer displays counts you supply.

  • Goal and process

    The original two-sigmoid illustration. Change process strength and explore the gap between a goal and access to it.

  • SAT benchmark

    Measured constructive success across system sizes, with an existence-side reference and the reported separation.

  • Trajectory atlas

    A synthetic illustration of paths with different fates. Explore the perspective of a single path and the surrounding field.

  • Trace visualizer

    An experimental browser tool for inspecting precomputed pool and survivor counts. It does not infer reachability from arbitrary project data.

  • Hidden process failure

    An illustrated explanation of why visible activity can continue after the route has changed.

  • AI measurement and supporting figures

    The published reasoning study, instrument anatomy, readout, and coarse-to-fine collapse.

  • ReachScan video explainer

    The original downloadable research explainer in MP4 format (22.9 MB).

Connect the research to a system you know.

For computational measurement, open software, domain research, or technical collaboration, describe the system, the question, and the records available.

Discuss a research connection
Earlier computational diagnostic reference documents

These documents describe the earlier computational pilot and its deliverables. For current engineering investigations, use the Diagnostic page; discuss computational measurement through the research contact above.