# Banach algebras with unique uniform norm II

Studia Mathematica (2001)

- Volume: 147, Issue: 3, page 211-235
- ISSN: 0039-3223

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topS. J. Bhatt, and H. V. Dedania. "Banach algebras with unique uniform norm II." Studia Mathematica 147.3 (2001): 211-235. <http://eudml.org/doc/284844>.

@article{S2001,

abstract = {Semisimple commutative Banach algebras 𝓐 admitting exactly one uniform norm (not necessarily complete) are investigated. 𝓐 has this Unique Uniform Norm Property iff the completion U(𝓐) of 𝓐 in the spectral radius r(·) has UUNP and, for any non-zero spectral synthesis ideal ℐ of U(𝓐), ℐ ∩ 𝓐 is non-zero. 𝓐 is regular iff U(𝓐) is regular and, for any spectral synthesis ideal ℐ of 𝓐, 𝓐/ℐ has UUNP iff U(𝓐) is regular and for any spectral synthesis ideal ℐ of U(𝓐), ℐ = k(h(𝓐 ∩ ℐ)) (hulls and kernels in U(𝓐)). 𝓐 has UUNP and the Shilov boundary coincides with the Gelfand space iff 𝓐 is weakly regular in the sense that, given a proper, closed subset F of the Gelfand space, there exists a non-zero x in 𝓐 having its Gelfand transform vanishing on F. Several classes of Banach algebras that are weakly regular but not regular, as well as those that are not weakly regular but have UUNP are exhibited. The UUNP is investigated for quotients, tensor products, and multiplier algebras. The property UUNP compares with the unique C*-norm property on (not necessarily commutative) Banach *-algebras. The results are applied to multivariate holomorphic function algebras as well as to the measure algebra of a locally compact abelian group G. For a continuous weight ω on G, the Beurling algebra L¹(G,ω) (assumed semisimple) has UUNP iff it is regular.},

author = {S. J. Bhatt, H. V. Dedania},

journal = {Studia Mathematica},

keywords = {unique uniform norm property; regular Banach algebras; unique -norm property; multipliers; tensor product; Beurling algebras; multivariate holomorphic function algebras; measure algebras},

language = {eng},

number = {3},

pages = {211-235},

title = {Banach algebras with unique uniform norm II},

url = {http://eudml.org/doc/284844},

volume = {147},

year = {2001},

}

TY - JOUR

AU - S. J. Bhatt

AU - H. V. Dedania

TI - Banach algebras with unique uniform norm II

JO - Studia Mathematica

PY - 2001

VL - 147

IS - 3

SP - 211

EP - 235

AB - Semisimple commutative Banach algebras 𝓐 admitting exactly one uniform norm (not necessarily complete) are investigated. 𝓐 has this Unique Uniform Norm Property iff the completion U(𝓐) of 𝓐 in the spectral radius r(·) has UUNP and, for any non-zero spectral synthesis ideal ℐ of U(𝓐), ℐ ∩ 𝓐 is non-zero. 𝓐 is regular iff U(𝓐) is regular and, for any spectral synthesis ideal ℐ of 𝓐, 𝓐/ℐ has UUNP iff U(𝓐) is regular and for any spectral synthesis ideal ℐ of U(𝓐), ℐ = k(h(𝓐 ∩ ℐ)) (hulls and kernels in U(𝓐)). 𝓐 has UUNP and the Shilov boundary coincides with the Gelfand space iff 𝓐 is weakly regular in the sense that, given a proper, closed subset F of the Gelfand space, there exists a non-zero x in 𝓐 having its Gelfand transform vanishing on F. Several classes of Banach algebras that are weakly regular but not regular, as well as those that are not weakly regular but have UUNP are exhibited. The UUNP is investigated for quotients, tensor products, and multiplier algebras. The property UUNP compares with the unique C*-norm property on (not necessarily commutative) Banach *-algebras. The results are applied to multivariate holomorphic function algebras as well as to the measure algebra of a locally compact abelian group G. For a continuous weight ω on G, the Beurling algebra L¹(G,ω) (assumed semisimple) has UUNP iff it is regular.

LA - eng

KW - unique uniform norm property; regular Banach algebras; unique -norm property; multipliers; tensor product; Beurling algebras; multivariate holomorphic function algebras; measure algebras

UR - http://eudml.org/doc/284844

ER -

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