C-star subalgebra
= C-star subalgebra
{c}
A C-star subalgebra is a norm-closed subalgebra closed under the involution, with the inherited <C-star identity>. A unital inclusion in this context uses the same identity as the ambient <C-star algebra>. The <spectral permanence for C-star algebras> says the inclusion preserves the <spectrum of an element>.