On operators from to or to
Christian Samuel (2010)
Colloquium Mathematicae
Similarity:
We show that every operator from to is compact when 1 ≤ p,q < s and that every operator from to is compact when 1/p + 1/q > 1 + 1/s.
Christian Samuel (2010)
Colloquium Mathematicae
Similarity:
We show that every operator from to is compact when 1 ≤ p,q < s and that every operator from to is compact when 1/p + 1/q > 1 + 1/s.
Hans Triebel (1994)
Studia Mathematica
Similarity:
Let , where the sum is taken over the lattice of all points k in having integer-valued components, j∈ℕ and . Let be either or (s ∈ ℝ, 0 < p < ∞, 0 < q ≤ ∞) on The aim of the paper is to clarify under what conditions is equivalent to .
Jorge Martinez, Warren Wm. McGovern (2022)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
In a Tychonoff space , the point is called a -point if every real-valued continuous function on can be extended continuously to . Every point in an extremally disconnected space is a -point. A classic example is the space consisting of the countable ordinals together with . The point is known to be a -point as well as a -point. We supply a characterization of -points in totally ordered spaces. The remainder of our time is aimed at studying when a point in a product space...
Václav Kryštof (2018)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We prove that for a normed linear space , if is continuous and semiconvex with modulus , is continuous and semiconcave with modulus and , then there exists such that . Using this result we prove a generalization of Ilmanen lemma (which deals with the case ) to the case of an arbitrary nontrivial modulus . This generalization (where a function is inserted) gives a positive answer to a problem formulated by A. Fathi and M. Zavidovique in 2010.
Reynaldo Rojas-Hernández (2015)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We show that any -product of at most -many -spaces has the -property. This result generalizes some known results about -spaces. On the other hand, we prove that every -product of monotonically monolithic spaces is monotonically monolithic, and in a similar form, we show that every -product of Collins-Roscoe spaces has the Collins-Roscoe property. These results generalize some known results about the Collins-Roscoe spaces and answer some questions due to Tkachuk [Lifting the Collins-Roscoe...
Haifeng Li, Leiyan Guo (2025)
Applications of Mathematics
Similarity:
We investigate the recovery of -sparse signals using the - minimization model with prior support set information. The prior support set information, which is believed to contain the indices of nonzero signal elements, significantly enhances the performance of compressive recovery by improving accuracy, efficiency, reducing complexity, expanding applicability, and enhancing robustness. We assume -sparse signals with the prior support which is composed of true indices and wrong...
Johannes Schleischitz (2020)
Communications in Mathematics
Similarity:
Following a suggestion of W.M. Schmidt and L. Summerer, we construct a proper -system with the property . In fact, our method generalizes to provide -systems with , for arbitrary . We visualize our constructions with graphics. We further present explicit examples of numbers that induce the -systems in question.
Shaban Khidr, Osama Abdelkader (2017)
Czechoslovak Mathematical Journal
Similarity:
Let be a -convex intersection, , , in a complex manifold of complex dimension , , and let be a holomorphic vector bundle of rank over . In this paper, -estimates, , for solutions to the -equation with small loss of smoothness are obtained for -valued -forms on when . In addition, we solve the -equation with a support condition in -spaces. More precisely, we prove that for a -closed form in , , , with compact support and for with there...
Sergei Logunov (2021)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We show that is not normal, if is a limit point of some countable subset of , consisting of points of character . Moreover, such a point is a Kunen point and a super Kunen point.
Wei-Feng Xuan, Wei-Xue Shi (2017)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
We prove that if is a first countable space with property and with a -diagonal then the cardinality of is at most . We also show that if is a first countable, DCCC, normal space then the extent of is at most .
Asma Ilkhanizadeh Manesh, Ahmad Mohammadhasani (2018)
Czechoslovak Mathematical Journal
Similarity:
For it is said that is gut-majorized by , and we write , if there exists an -by- upper triangular g-row stochastic matrix such that . Define the relation as follows. if is gut-majorized by and is gut-majorized by . The (strong) linear preservers of on and strong linear preservers of this relation on have been characterized before. This paper characterizes all (strong) linear preservers and strong linear preservers of on and .
Igor Protasov (2022)
Commentationes Mathematicae Universitatis Carolinae
Similarity:
Given a coarse space with the bornology of bounded subsets, we extend the coarse structure from to the natural coarse structure on and say that a macro-uniform mapping (or ) is a selector (or 2-selector) of if for each (, respectively). We prove that a discrete coarse space admits a selector if and only if admits a 2-selector if and only if there exists a linear order “" on such that the family of intervals is a base for the bornology .