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Continuous functions on primal topological spaces induced by group actions
AIMS Mathematics 2025, 10(1): 793-808
Published: 15 January 2025
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If G is a group acting on a set X, then for any a G, the restriction ϕ a : X X of the action to a induces a topology τ a for X, called the primal topology induced by ϕ a . First, we obtain a characterization of the normal subgroups in terms of the primal topologies. Later, we prove that some commutative relations among elements on the group G determine the continuity of maps among different primal spaces ( X , τ ϕ x ). In particular, we prove the continuity of some maps when a , b , q G satisfy a quantum type relation, b a = q a b, as is in the quaternion and Heisenberg groups.

Open Access Research Article Issue
The property (ωπ) as a generalization of the a-Weyl theorem
AIMS Mathematics 2024, 9(9): 25646-25658
Published: 15 September 2024
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In this paper, for a bounded linear operator defined on a complex Banach space of infinite dimension, we consider the set of isolated points in its approximate point spectrum, which are eigenvalues of finite multiplicity; this set can be equal to the spectrum of the operator but without its upper semi-Fredholm spectrum, and this relation or equality defines in the literature a new spectral property called the property (ωπ) and is a generalization of the classical a-Weyl theorem. We establish some characterizations and consequences about the property (ωπ), some with topological aspects. Furthermore, we study this property through the Riesz functional calculus. Part of the spectral structure of a linear operator verifying property (ωπ) is described, obtaining some associated properties.

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