= Hermitian element of a star algebra
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{title2=$h^*=h$}
= Self-adjoint element of a star algebra
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= Hermitian algebra element
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{synonym}
A <Hermitian algebra element> of a <star-algebra> is an element fixed by its <algebra involution>. The identity and zero are <Hermitian algebra elements>. For every $x$, both $xx^*$ and $x^*x$ are <Hermitian algebra elements>. A real spectrum for all such elements is an extra condition in a general <Banach algebra>, rather than a consequence of the involution identities alone.
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