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EP elements in rings with involution. (English) Zbl 1432.16035

Summary: Let \(R\) be a with involution. We first show that the EP elements in \(R\) can be characterized by three equations. Namely, let \(a\in R\), then \(a\) is EP if and only if there exists \(x\in R\) such that \((xa)^\ast=xa, xa^2=a\) and \(ax^2=x.\) Any EP element in \(R\) is core invertible and Moore-Penrose invertible. We give more equivalent conditions for a core (Moore-Penrose) to be an EP element. Finally, any EP element is characterized in terms of the \(n\)-EP property, which is a generalization of the bi-EP property.

MSC:

16W10 Rings with involution; Lie, Jordan and other nonassociative structures
16U90 Generalized inverses (associative rings and algebras)

References:

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