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Record W2776185042 · doi:10.4171/ggd/524

Panel collapse and its applications

2019· article· en· W2776185042 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueGroups Geometry and Dynamics · 2019
Typearticle
Languageen
FieldMaterials Science
TopicQuasicrystal Structures and Properties
Canadian institutionsUniversity of New Brunswick
FundersEngineering and Physical Sciences Research Council
KeywordsHyperplaneCube (algebra)Rigidity (electromagnetism)Subspace topologyGroup (periodic table)

Abstract

fetched live from OpenAlex

We describe a procedure called panel collapse for replacing a CAT(0) cube complex \Psi by a "lower complexity" CAT(0) cube complex \Psi_\bullet whenever \Psi contains a codimension-2 hyperplane that is extremal in one of the codimension-1 hyperplanes containing it. Although \Psi_\bullet is not in general a subcomplex of \Psi , it is a subspace consisting of a subcomplex together with some cubes that sit inside \Psi "diagonally." The hyperplanes of \Psi_\bullet extend to hyperplanes of \Psi . Applying this procedure, we prove: if a group G acts cocompactly on a CAT(0) cube complex \Psi , then there is a CAT(0) cube complex \Omega so that G acts cocompactly on \Omega and for each hyperplane H of \Omega , the stabiliser in G of H acts on H essentially. Using panel collapse, we obtain a new proof of Stallings's theorem on groups with more than one end. As another illustrative example, we show that panel collapse applies to the exotic cubulations of free groups constructed by Wise in [44]. Next, we show that the CAT(0) cube complexes constructed by Cashen and Macura in [7] can be collapsed to trees while preserving all of the necessary group actions. (It also illustrates that our result applies to actions of some non-discrete groups.) We also discuss possible applications to quasi-isometric rigidity for certain classes of graphs of free groups with cyclic edge groups. Panel collapse is also used in forthcoming work of the first-named author and Wilton to study fixed-point sets of finite subgroups of Out (F_n) on the free splitting complex. Finally, we apply panel collapse to a conjecture of Kropholler, obtaining a short proof under a natural extra hypothesis.

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Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.444
Threshold uncertainty score0.285

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.010
GPT teacher head0.206
Teacher spread0.196 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it