Results 31 to 40 of about 93 (67)

An Improved Computationally Efficient Method for Finding the Drazin Inverse

Discrete Dynamics in Nature and Society, Volume 2018, Issue 1, 2018., 2018
Drazin inverse is one of the most significant inverses in the matrix theory, where its computation is an intensive and useful task. The objective of this work is to propose a computationally effective iterative scheme for finding the Drazin inverse. The convergence is investigated analytically by applying a suitable initial matrix.
Haifa Bin Jebreen, Yurilev Chalco-Cano, Tarek F. Ibrahim   +2 more
wiley   +1 more source

Finite models for positive combinatorial and exponential algebra

Bulletin of the London Mathematical Society, Volume 57, Issue 11, Page 3380-3400, November 2025.
Abstract We use high girth, high chromatic number hypergraphs to show that there are finite models of the equational theory of the semiring of non‐negative integers whose equational theory has no finite axiomatisation, and show this also holds if factorial, fixed base exponentiation and operations for binomial coefficients are adjoined.
Tumadhir Alsulami, Marcel Jackson
wiley   +1 more source

On Endomorphism Universality of Sparse Graph Classes

Journal of Graph Theory, Volume 110, Issue 2, Page 223-244, October 2025.
ABSTRACT We show that every commutative idempotent monoid (a.k.a. lattice) is the endomorphism monoid of a subcubic graph. This solves a problem of Babai and Pultr and the degree bound is best‐possible. On the other hand, we show that no class excluding a minor can have all commutative idempotent monoids among its endomorphism monoids. As a by‐product,
Kolja Knauer, Gil Puig i Surroca
wiley   +1 more source

On Maximal Subsemigroups of Partial Baer‐Levi Semigroups

International Journal of Mathematics and Mathematical Sciences, Volume 2011, Issue 1, 2011., 2011
Suppose that X is an infinite set with |X | ≥ q ≥ ℵ0 and I(X) is the symmetric inverse semigroup defined on X. In 1984, Levi and Wood determined a class of maximal subsemigroups MA (using certain subsets A of X) of the Baer‐Levi semigroup BL(q) = {α ∈ I(X): dom α = X and |X∖Xα| = q}.
Boorapa Singha, Jintana Sanwong, Robert Redfield   +2 more
wiley   +1 more source

A coboundary Temperley–Lieb category for sl2$\mathfrak {sl}_{2}$‐crystals

Journal of the London Mathematical Society, Volume 112, Issue 3, September 2025.
Abstract By considering a suitable renormalization of the Temperley–Lieb category, we study its specialization to the case q=0$q=0$. Unlike the q≠0$q\ne 0$ case, the obtained monoidal category, TL0(k)$\mathcal {TL}_0(\mathbb {k})$, is not rigid or braided. We provide a closed formula for the Jones–Wenzl projectors in TL0(k)$\mathcal {TL}_0(\mathbb {k})$
Moaaz Alqady, Mateusz Stroiński
wiley   +1 more source

On the Necessary and Sufficient Condition for a Set of Matrices to Commute and Some Further Linked Results

Mathematical Problems in Engineering, Volume 2009, Issue 1, 2009., 2009
This paper investigates the necessary and sufficient condition for a set of (real or complex) matrices to commute. It is proved that the commutator [A, B] = 0 for two matrices A and B if and only if a vector v(B) defined uniquely from the matrix B is in the null space of a well‐structured matrix defined as the Kronecker sum A ⊕ (−A∗), which is always ...
M. De La Sen, Angelo Luongo
wiley   +1 more source

Traces on the uniform tracial completion of Z$\mathcal {Z}$‐stable C∗${\rm C}^*$‐algebras

Journal of the London Mathematical Society, Volume 111, Issue 6, June 2025.
Abstract The uniform tracial completion of a C∗${\rm C}^*$‐algebra A$A$ with compact trace space T(A)≠∅$T(A) \ne \emptyset$ is obtained by completing the unit ball with respect to the uniform 2‐seminorm ∥a∥2,T(A)=supτ∈T(A)τ(a∗a)1/2$\Vert a\Vert _{2,T(A)}=\sup _{\tau \in T(A)} \tau (a^*a)^{1/2}$. The trace problem asks whether every trace on the uniform
Samuel Evington
wiley   +1 more source

Unipotency of Matrix Group Generated by Two Matrices

Journal of Applied Mathematics, Volume 2025, Issue 1, 2025.
In this paper, the problem of unipotency for the matrix group generated by two matrices is examined. By employing matrix logarithms as a tool, various combinatorial formulas for matrices were derived by selecting different primitive elements. Key conclusions were then reached through the organization and simplification of these formulas.
Yanshuo Cheng, Xinsong Yang, Kamal Kumar
wiley   +1 more source

Weak ω‐Approximate Biprojectivity of Banach Algebras

Journal of Mathematics, Volume 2025, Issue 1, 2025.
For a given Banach algebra M and a continuous endomorphism ω on M, we define weakly ω‐approximately biprojective and weakly ω‐approximately Helemskii biflat Banach algebras. We then examine the relationship between them and express the correlation between them and ω‐pseudoamenability.
Zahra Ghorbani, Elena Guardo
wiley   +1 more source

Characterizing Topologically Dense Injective Acts and Their Monoid Connections

Journal of Mathematics, Volume 2024, Issue 1, 2024.
In this paper, we explore the concept of topologically dense injectivity of monoid acts. It is shown that topologically dense injective acts constitute a class strictly larger than the class of ordinary injective ones. We determine a number of acts satisfying topologically dense injectivity.
Masoomeh Hezarjaribi Dastaki, Hamid Rasouli, Hasan Barzegar, G. Muhiuddin   +3 more
wiley   +1 more source