activity
20112026
most citedAlmost all matroids are non-representable

18 citations · 38 across the 33 of their papers we have counts for

collaborators

44 papers

math.CO2026

Modularity, Extensions and Connectivity in Infinite Matroids

Mattias Ehatamm, Peter Nelson, Fernanda Rivera Omana

We generalize the well-studied notion of a modular pair of a finite matroid to arbitrary families of sets in infinite matroids, and use it to develop the theory of infinite matroid…

math.CO2025

Composition Direction of Seymour's Theorem for Regular Matroids -- Formally Verified

Martin Dvorak, Tristan Figueroa-Reid, Rida Hamadani +8

Seymour's decomposition theorem is a hallmark result in matroid theory presenting a structural characterization of the class of regular matroids. Formalization of matroid theory fa…

cs.SC2025

Structuring Definitions in Mathematical Libraries

Alena Gusakov, Peter Nelson, Stephen Watt

Codifying mathematical theories in a proof assistant or computer algebra system is a challenging task, of which the most difficult part is, counterintuitively, structuring definiti…

math.CO2025

Rainbow triangles and the Erdős-Hajnal problem in projective geometries

Carolyn Chun, James Dylan Douthitt, Wayne Ge +3

We formulate a geometric version of the Erdős-Hajnal conjecture that applies to finite projective geometries rather than graphs, in both its usual 'induced' form and the multicolou…

math.CO2023

Minors of matroids represented by sparse random matrices over finite fields

Pu Gao, Peter Nelson

Consider a random matrix over the finite field of order where every column has precisely nonzero elements, and let be the matroid represented by .…

math.CO2023

On the density of matroids omitting a complete-graphic minor

Peter Nelson, Sergey Norin, Fernanda Rivera Omana

We show that, if is a simple rank- matroid with no -point line minor and no minor isomorphic to the cycle matroid of a -vertex complete graph, then the ratio $|M| /…