On Componental Operators in Hilbert Space

التفاصيل البيبلوغرافية
العنوان: On Componental Operators in Hilbert Space
المؤلفون: Cegielski, Andrzej, Censor, Yair
سنة النشر: 2021
المجموعة: Mathematics
مصطلحات موضوعية: Mathematics - Functional Analysis, Mathematics - Optimization and Control
الوصف: We consider a Hilbert space that is a product of a finite number of Hilbert spaces and operators that are represented by "componental operators" acting on the Hilbert spaces that form the product space. We attribute operatorial properties to the componental operators rather than to the full operators. The operatorial properties that we discuss include nonexpansivity, firm non-expansivity, relaxed firm nonexpansivity, averagedness, being a cutter, quasi-nonexpansivity, strong quasi-nonexpansivity, strict quasi-nonexpansivity and contraction. Some relationships between operators whose componental operators have such properties and operators that have these properties on the product space are studied. This enables also to define componental fixed point sets and to study their properties. For componental contractions we offer a variant of the Banach fixed point theorem. Our motivation comes from the desire to extend a fully-simultaneous method that takes into account sparsity of the linear system in order to accelerate convergence [Censor et al., On diagonally relaxed orthogonal projection methods, SIAM J. Sci. Comput. 30 (2008), 473-504]. This was originally applicable to the linear case only and gives rise to an iterative process that uses dfferent componental operators during iterations.
Comment: 18 pages. Accepted for publication in: Numerical Functional Analysis and Optimization
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2111.02830
رقم الأكسشن: edsarx.2111.02830
قاعدة البيانات: arXiv