Results 71 to 80 of about 564 (182)
Recognising flag varieties and reductive groups
Proceedings of the London Mathematical Society, Volume 133, Issue 2, August 2026.Abstract Fix a flat and projective morphism X→Σ$X\rightarrow \Sigma$ of schemes. We show, first, that any set of P1${\mathbb {P}}^1$‐fibrations on X$X$ defines a set of simple roots, a set of simple coroots and a Cartan matrix C$C$. Second, X$X$ is an étale F${\mathcal {F}}$‐bundle over some projective Σ$\Sigma$‐scheme, where F${\mathcal {F}}$ is the ...
Ian Grojnowski +1 more
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The Frobenius distances from projections to an idempotent matrix
Linear Algebra and its ApplicationsFor each pair of matrices $A$ and $B$ with the same order, let $\|A-B\|_F$ denote their Frobenius distance. This paper deals mainly with the Frobenius distances from projections to an idempotent matrix. For every idempotent $Q\in \mathbb{C}^{n\times n}$, a projection $m(Q)$ called the matched projection can be induced.
Xiaoyi Tian, Qingxiang Xu, Chunhong Fu
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Proceedings of the London Mathematical Society, Volume 133, Issue 2, August 2026.Abstract This paper investigates the maximal subgroups of a free projection‐generated regular ∗$*$‐semigroup PG(P)${{\textsf {PG}}}(P)$ over a projection algebra P$P$, and their relationship to the maximal subgroups of the free idempotent‐generated semigroup IG(E)${{\textsf {IG}}}(E)$ over the corresponding biordered set E=E(P)$E = {{\textsf {E}}}(P)$.
James East +3 more
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Eigenvector-Free Solutions to the Matrix Equation AXBH=E with Two Special Constraints
Journal of Applied Mathematics, 2013 The matrix equation AXBH=E with SX=XR or PX=sXQ constraint is considered, where S, R are Hermitian idempotent, P, Q are Hermitian involutory, and s=±1.
Yuyang Qiu
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Rings whose non-units are square-nil clean [PDF]
Arab Journal of Mathematical SciencesPurposeTo describe the structure of a special sort of rings whose non-invertible elements are the sum of a nilpotent and a square-idempotent (which commute one another).
Mina Doostalizadeh +2 more
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Local Polynomial Regression and Filtering for a Versatile Mesh‐Free PDE Solver
International Journal for Numerical Methods in Fluids, Volume 98, Issue 7, Page 804-839, July 2026.A high‐order, mesh‐free finite difference method for solving differential equations is presented. Both derivative approximation and scheme stabilisation is carried out by parametric or non‐parametric local polynomial regression, making the resulting numerical method accurate, simple and versatile. Numerous numerical benchmark tests are investigated for
Alberto M. Gambaruto
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On Quadraticity of Linear Combinations of Two Essentially Cubic Matrices That Commute
AxiomsThis work presents a complete and definitive characterization of all cases where every linear combination of two commuting essentially cubic matrices results in a quadratic matrix, thereby extending existing contributions in the literature. To facilitate
Tuğba Demirkol, İrem Gamze Ünlütürk
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Maps on matrix algebras preserving idempotents
Linear Algebra and its Applications, 2003 Let \(M_n({\mathbb C})\) be the algebra of all \(n\times n\) matrices with entries from the field of complex numbers \({\mathbb C}\), \(P_n\) be the set of all idempotents in \(M_n({\mathbb C})\). \textit{P. Šemrl} [ibid. 361, 161-179 (2003; Zbl 1035.15004)], characterized bijective continuous maps \(T : M_n({\mathbb C}) \to M_n({\mathbb C})\), \(n\geq
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On the Idempotent Graph of Matrix Ring
13 pages, 1 ...
Patil, Avinash +2 more
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Idempotency of the Hermitian part of a complex matrix
Linear Algebra and its Applications, 1999 The paper characterizes matrices \(A\) with the Hermitian part, \(H(A)= (A + A^*)/2,\) being idempotent. It is shown that such matrices belong to the class of complex \(m\times m\) matrices for which \(A A^+ = A^+ A,\) where \(A^+\) is the Moore-Penrose inverse of \(A\), or equivalently, the range of \(A\) equals the range of \(A^*\).
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