Results 61 to 70 of about 4,009 (153)

Axioms for infinite matroids

open access: yes, 2012
We give axiomatic foundations for non-finitary infinite matroids with duality, in terms of independent sets, bases, circuits, closure and rank.
Bruhn, Henning   +4 more
core   +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

Parametric matroid of rough set [PDF]

open access: yes, 2012
Rough set is mainly concerned with the approximations of objects through an equivalence relation on a universe. Matroid is a combinatorial generalization of linear independence in vector spaces.
Liu, Yanfang, Zhu, William
core  

Bases in oriented matroids

open access: yesJournal of Combinatorial Theory, Series B, 1978
AbstractLet M be an oriented matroid. One can define exactly two assignments of +1 and −1 to permutations of bases of M canonically associated with the orientation of M.
openaire   +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

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

Efficient and strategy‐proof mechanism under general constraints

open access: yesTheoretical Economics, Volume 20, Issue 2, Page 481-509, May 2025.
This study investigates efficient and strategy‐proof mechanisms for allocating indivisible goods under constraints. First, we examine a setting without endowments. In this setting, we introduce a class of constraints—ordered accessibility—for which the serial dictatorship (SD) mechanism is Pareto‐efficient (PE), individually rational (IR), and group ...
Kenzo Imamura, Yasushi Kawase
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

On Greedy Bases Packing in Matroids

open access: yesEuropean Journal of Combinatorics, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +1 more source

Basilica: New canonical decomposition in matching theory

open access: yesJournal of Graph Theory, Volume 108, Issue 3, Page 508-542, March 2025.
Abstract In matching theory, one of the most fundamental and classical branches of combinatorics, canonical decompositions of graphs are powerful and versatile tools that form the basis of this theory. However, the abilities of the known canonical decompositions, that is, the Dulmage–Mendelsohn, Kotzig–Lovász, and Gallai–Edmonds decompositions, are ...
Nanao Kita
wiley   +1 more source

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