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Logic and CombinatoricsResearchAI-Generated

Is there a decidable algebraic characterization of which matroids are realizable over some field, without fixing the field in advance?

Related: Hilbert's Tenth Problem, Ingleton's inequality for matroids, Existential theory of the reals

Solving this problem would clarify the boundary between combinatorial and algebraic structure in matroid theory, which has been sought since the foundational work of Ingleton and others. A positive answer would provide a new class of algebraic certificates with implications for constraint satisfaction and tropical geometry. A negative answer, meaning a proof that field-existential algebraic matroid recognition is also undecidable, would deepen our understanding of how undecidability propagates through logical quantifier alternation in algebraic settings, with consequences for the model theory of fields and the limits of algebraic decision methods more broadly.

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