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On the growth of analytic semigroups along vertical lines

José Galé, Thomas Ransford (2000)

Studia Mathematica

We construct two Banach algebras, one which contains analytic semigroups ( a z ) R e z > 0 such that | a 1 + i y | arbitrarily slowly as | y | , the other which contains ones such that | a 1 + i y | arbitrarily fast

On the ideal structure of algebras of LMC-algebra valued functions

Jorma Arhippainen (1992)

Studia Mathematica

Let X be a completely regular topological space and A a commutative locally m-convex algebra. We give a description of all closed and in particular closed maximal ideals of the algebra C(X,A) (= all continuous A-valued functions defined on X). The topology on C(X,A) is defined by a certain family of seminorms. The compact-open topology of C(X,A) is a special case of this topology.

On the joint spectral radius

Vladimír Müller (1997)

Annales Polonici Mathematici

We prove the p -spectral radius formula for n-tuples of commuting Banach algebra elements

On the Lipschitz operator algebras

A. Ebadian, A. A. Shokri (2009)

Archivum Mathematicum

In a recent paper by H. X. Cao, J. H. Zhang and Z. B. Xu an α -Lipschitz operator from a compact metric space into a Banach space A is defined and characterized in a natural way in the sence that F : K A is a α -Lipschitz operator if and only if for each σ X * the mapping σ F is a α -Lipschitz function. The Lipschitz operators algebras L α ( K , A ) and l α ( K , A ) are developed here further, and we study their amenability and weak amenability of these algebras. Moreover, we prove an interesting result that L α ( K , A ) and l α ( K , A ) are isometrically...

On the maximal Fejér operator for double Fourier series of functions in Hardy spaces

Ferenc Móricz (1995)

Studia Mathematica

We consider the Fejér (or first arithmetic) means of double Fourier series of functions belonging to one of the Hardy spaces H ( 1 , 0 ) ( 2 ) , H ( 0 , 1 ) ( 2 ) , or H ( 1 , 1 ) ( 2 ) . We prove that the maximal Fejér operator is bounded from H ( 1 , 0 ) ( 2 ) or H ( 0 , 1 ) ( 2 ) into weak- L 1 ( 2 ) , and also bounded from H ( 1 , 1 ) ( 2 ) into L 1 ( 2 ) . These results extend those by Jessen, Marcinkiewicz, and Zygmund, which involve the function spaces L 1 l o g + L ( 2 ) , L 1 ( l o g + L ) 2 ( 2 ) , and L μ ( 2 ) with 0 < μ < 1, respectively. We establish analogous results for the maximal conjugate Fejér operators. On closing, we formulate two conjectures....

On the non-existence of norms for some algebras of functions

Bertram Yood (1994)

Studia Mathematica

Let C(Ω) be the algebra of all complex-valued continuous functions on a topological space Ω where C(Ω) contains unbounded functions. First it is shown that C(Ω) cannot have a Banach algebra norm. Then it is shown that, for certain Ω, C(Ω) cannot possess an (incomplete) normed algebra norm. In particular, this is so for Ω = n where ℝ is the reals.

On the product property of the Carathéodory pseudodistance

José M. Isidro, Jean-Pierre Vigué (2000)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

We prove that, for certain domains D , continuous product of domains D ω , the Carathéodory pseudodistance satisfies the following product property C D f , g = sup ω C D ω f ω , g ω

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