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Record W2609243979 · doi:10.1090/crmp/035/13

Compressions of group actions

2004· book-chapter· en· W2609243979 on OpenAlex
Zinovy Reichstein

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

VenueCRM proceedings & lecture notes · 2004
Typebook-chapter
Languageen
FieldMathematics
TopicGeometric and Algebraic Topology
Canadian institutionsUniversity of British ColumbiaNatural Sciences and Engineering Research Council of Canada
Fundersnot available
KeywordsGroup (periodic table)Group actionPsychologyPhysics

Abstract

fetched live from OpenAlex

Let G be a finite group. A G-variety X is an algebraic variety with a regular G-action; X is faithful if every 1 6 = g ∈ G acts non-trivially. I will refer to a dominant G-equivariant rational (respectively, regular) map of faithful G-varieties as a rational (respectively, regular) compression. All varieties, actions, vector spaces, maps, etc., are assumed to be defined over a fixed algebraically closed base field k of characteristic zero; all varieties are assumed to be irreducible. I would like to thank V. L. Popov for stimulating discussions and for helpful comments on an earlier draft of this note. 1. Essential dimension Let V be a faithful linear representation of G and let d be the minimal value of dim(X), where the minimum is taken over all rational compressions f: V 99K X. Note that (a) (see [1, Theorem 3.1] or [6, Theorem 3.4(b)]) d depends only on the group G and not on the choice of V, and (b) (cf. [6, Proposition 7.1]) in the definition of d we may assume that X is a G-invariant subvariety of V, i.e., X is the closure of the image of a rational covariant f: V 99K V. The number d is called the essential dimension of G and is usually denoted by ed(G). This number has interesting connections with the algebraic form of Hilbert’s 13th problem, cohomological invariants, generic polynomials and other topics; these connections are described in [1] and [2]. The case where G = Sn is of particular interest. (The notion of essential dimension is also of interest in the context of algebraic groups; see [6] and [7].) Problem 1. Find ed(G) and, in particular, ed(Sn). The value of ed(G) is known if G is an abelian group; see [1, Theorem 6.1]. For symmetric groups, ed(Sn) ≥ [n/2]; this is proved, in different ways,

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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)0.001
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.992
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0020.000

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 head0.060
GPT teacher head0.299
Teacher spread0.239 · 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