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Record W1975863402 · doi:10.4153/cmb-2000-053-3

Nonconvexity of the Generalized Numerical Range Associated with the Principal Character

2000· article· en· W1975863402 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.
fundA Canadian funder is recorded on the work.
venuePublished in a venue whose home country is Canada.

Bibliographic record

VenueCanadian Mathematical Bulletin · 2000
Typearticle
Languageen
FieldComputer Science
TopicMatrix Theory and Algorithms
Canadian institutionsUniversity of Toronto
FundersUniversity of TorontoNational Science Foundation
KeywordsMathematicsCombinatoricsNumerical rangeHermitian matrixEigenvalues and eigenvectorsNormal matrixMatrix (chemical analysis)Regular polygonPure mathematicsGeometryPhysics

Abstract

fetched live from OpenAlex

Abstract Suppose m and n are integers such that 1 ≤ m ≤ n . For a subgroup H of the symmetric group S m of degree m , consider the generalized matrix function on m × m matrices B = (b ij ) defined by and the generalized numerical range of an n × n complex matrix A associated with d H defined by It is known that W H ( A ) is convex if m = 1 or if m = n = 2. We show that there exist normal matrices A for which W H (A) is not convex if 3 ≤ m ≤ n . Moreover, for m = 2 < n , we prove that a normal matrix A with eigenvalues lying on a straight line has convex W H (A) if and only if ν A is Hermitian for some nonzero ν ∈ ℂ . These results extend those of Hu, Hurley and Tam, who studied the special case when 2 ≤ m ≤ 3 ≤ n and H = S m .

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

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)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.874
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
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 science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0100.001

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 head0.196
Teacher spread0.187 · 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