Results 61 to 70 of about 9,755 (179)

Matroidal Structure of Rough Sets Based on Serial and Transitive Relations

open access: yesJournal of Applied Mathematics, 2012
The theory of rough sets is concerned with the lower and upper approximations of objects through a binary relation on a universe. It has been applied to machine learning, knowledge discovery, and data mining. The theory of matroids is a generalization of
Yanfang Liu, William Zhu
doaj   +1 more source

Exterior algebras in matroid theory

open access: yesmanuscripta mathematica, 2022
AbstractOrdered blueprints are algebraic objects that generalize monoids and ordered semirings, and $$\mathbb {F}_1^{\pm }$$ F 1 ± -algebras are ordered blueprints that have an element $$\epsilon $$ ϵ that
openaire   +3 more sources

A circle method approach to K‐multimagic squares

open access: yesJournal of the London Mathematical Society, Volume 112, Issue 3, September 2025.
Abstract In this paper, we investigate K$K$‐multimagic squares of order N$N$. These are N×N$N \times N$ magic squares that remain magic after raising each element to the k$k$th power for all 2⩽k⩽K$2 \leqslant k \leqslant K$. Given K⩾2$K \geqslant 2$, we consider the problem of establishing the smallest integer N2(K)$N_2(K)$ for which there exist ...
Daniel Flores
wiley   +1 more source

Positively oriented matroids are realizable [PDF]

open access: yes, 2013
We prove da Silva's 1987 conjecture that any positively oriented matroid is a positroid; that is, it can be realized by a set of vectors in a real vector space.
Ardila, Federico   +2 more
core  

Foundations for a theory of complex matroids

open access: yes, 2012
We explore a combinatorial theory of linear dependency in complex space, "complex matroids", with foundations analogous to those for oriented matroids.
Anderson, Laura, Delucchi, Emanuele
core   +1 more source

Note on Hamiltonicity of Basis Graphs of Even Delta‐Matroids

open access: yesJournal of Graph Theory, Volume 109, Issue 4, Page 446-453, August 2025.
ABSTRACT We show that the basis graph of an even delta‐matroid is Hamiltonian if it has more than two vertices. More strongly, we prove that for two distinct edges e and f sharing a common end, it has a Hamiltonian cycle using e and avoiding f unless it has at most two vertices or it is a cycle of length at most four.
Donggyu Kim, Sang‐il Oum
wiley   +1 more source

Geometric Lattice Structure of Covering-Based Rough Sets through Matroids

open access: yesJournal of Applied Mathematics, 2012
Covering-based rough set theory is a useful tool to deal with inexact, uncertain, or vague knowledge in information systems. Geometric lattice has been widely used in diverse fields, especially search algorithm design, which plays an important role in ...
Aiping Huang, William Zhu
doaj   +1 more source

Matroid Inequalities from Electrical Network Theory [PDF]

open access: yesThe Electronic Journal of Combinatorics, 2005
In 1981, Stanley applied the Aleksandrov–Fenchel Inequalities to prove a logarithmic concavity theorem for regular matroids. Using ideas from electrical network theory we prove a generalization of this for the wider class of matroids with the "half–plane property".
openaire   +2 more sources

Generic root counts and flatness in tropical geometry

open access: yesJournal of the London Mathematical Society, Volume 111, Issue 5, May 2025.
Abstract We use tropical and nonarchimedean geometry to study the generic number of solutions of families of polynomial equations over a parameter space Y$Y$. In particular, we are interested in the choices of parameters for which the generic root count is attained.
Paul Alexander Helminck, Yue Ren
wiley   +1 more source

New building blocks for F1${\mathbb {F}}_1$‐geometry: Bands and band schemes

open access: yesJournal of the London Mathematical Society, Volume 111, Issue 4, April 2025.
Abstract We develop and study a generalization of commutative rings called bands, along with the corresponding geometric theory of band schemes. Bands generalize both hyperrings, in the sense of Krasner, and partial fields in the sense of Semple and Whittle.
Matthew Baker   +2 more
wiley   +1 more source

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