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Record W3204184250 · doi:10.5802/alco.263

Lagrangian combinatorics of matroids

2023· article· en· W3204184250 on OpenAlexfundno aff
Federico Ardila, Graham Denham, June Huh

Bibliographic record

VenueAlgebraic Combinatorics · 2023
Typearticle
Languageen
FieldMathematics
TopicAdvanced Combinatorial Mathematics
Canadian institutionsnot available
FundersSimons Institute for the Theory of Computing, University of California BerkeleyNatural Sciences and Engineering Research Council of CanadaSorbonne UniversitéUniversità di BolognaDivision of Mathematical SciencesNational Science Foundation
KeywordsMatroidMathematicsLagrangianPiecewise linear functionCombinatoricsRegular polygonConjecturePiecewisePure mathematicsGeometryMathematical analysis

Abstract

fetched live from OpenAlex

The Lagrangian geometry of matroids was introduced in [2] through the construction of the conormal fan of a matroid M . We used the conormal fan to give a Lagrangian-geometric interpretation of the h -vector of the broken circuit complex of M : its entries are the degrees of the mixed intersections of certain convex piecewise linear functions γ and δ on the conormal fan of M . By showing that the conormal fan satisfies the Hodge-Riemann relations, we proved Brylawski’s conjecture that this h -vector is a log-concave sequence. This sequel explores the Lagrangian combinatorics of matroids , further developing the combinatorics of biflats and biflags of a matroid, and relating them to the theory of basis activities developed by Tutte, Crapo, and Las Vergnas. Our main result is a combinatorial realization of the intersection-theoretic computation above: we write the k -th mixed intersection of γ and δ explicitly as a sum of biflags corresponding to the nbc bases of internal activity k + 1 .

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.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
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 score0.012
Threshold uncertainty score0.042

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0030.002
Science and technology studies0.0020.003
Scholarly communication0.0040.005
Open science0.0010.002
Research integrity0.0010.002
Insufficient payload (model declined to judge)0.0120.002

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 head0.041
GPT teacher head0.319
Teacher spread0.278 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations4
Published2023
Admission routes1
Has abstractyes

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