On almost commutative unital complex normed Q-algebras

Authors

  • C. Benchakroun Université Mohammed V de Rabat, Marocco
  • A. El Kinani Universite ́ Mohammed V de Rabat, Marocco

Abstract

We show that a unital complex normed Q-algebra (A,∥.∥) in which the spectral radius satisfies:

ρA(x) = inf{p(x) : p ∈ Eun(A), p ≤ ∥.∥},

where Eun(A) denotes the set of all algebra-norms p on A equivalent to the given algebra-norm ∥.∥ such that p(e) = 1, is commutative modulo its Jacobson radical. The same conclusion is obtained if (A, ∥.∥) satisfies:

ρAb(xy) ≤ ρAb(x) ∥y∥ for every x ∈ Ab, y ∈ A, where Ab is the completion of (A, ∥.∥).

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Published

2025-12-05

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Section

Articoli