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On the Mappings Preserving Equality of 2-Distance
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Wei-Jia Jia* --- School of Mathematics Science, P.R. ChinaIn this paper, we consider 2-isometries, 2-continuous mappings and mappings preserving equality of 2-distance and investigate the relation between the three mappings in linear 2-normed spaces. We prove that if f: E → F is a mapping preserving equality of... -
Approximate local isometries of derivative Hardy spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: A. Jiménez-Vargas --- Universidad de Almería, Spain Takeshi Miura --- Niigata University, JapanFor any 1 ≤ p ≤ ∞, let Sp () be the space of holomorphic functions f on such that f′ belongs to the Hardy space Hp (), with the norm ∥f∥∑ = ||f||∞ +||f′|| p . We prove that... -
Exploring new solutions to Tingley’s problem for function algebras
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: María Cueto-Avellaneda --- University of Kent, UK Daisuke Hirota --- Niigata University, Japan Takeshi Miura --- Niigata University, Japan Antonio M. Peralta --- Instituto de Matemáticas de la Universidad de Granada (IMAG), SpainIn this note we present two new positive answers to Tingley’s problem in certain subspaces of function algebras. In the first result we prove that every surjective isometry between the unit spheres, S(A) and S(B), of two uniformly closed function... -
A note on partial-A-isometries and some applications
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Mohamed Amine Aouichaoui --- Institute of Preparatory Studies in Engineering of Monastir Tunisia, University of Monastir, TunisiaIn this paper, the concepts of partial isometry and A-isometry are generalized. The inspiration for our investigation comes from [4, 10, 20, 27, 28, 29]. -
On EP matrices, partial isometry matrices and their numerical range
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Gholamreza Aghamollaei --- Shahid Bahonar University of Kerman, Iran Mahdiyeh Mortezaei --- Shahid Bahonar University of Kerman, Iran Mohammad Ali Nourollahi --- , IranIn this paper, some properties of the numerical range of some well-known generalized inverses of matrices, such as Moore-Penrose inverse, Drazin inverse, DMP inverse and CMP inverse, are investigated. In particular, an identification of EP matrices is given via the...