# Category:Element of Unital Banach Algebra on Boundary of Group of Units of Subalgebra is Not Invertible in Algebra

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This category contains pages concerning **Element of Unital Banach Algebra on Boundary of Group of Units of Subalgebra is Not Invertible in Algebra**:

Let $\struct {A, \norm {\, \cdot \,} }$ be a unital Banach algebra.

Let $\map G A$ be the group of units of $A$.

Let $B$ be a closed subalgebra of $A$.

Let $\map G B$ be the group of units of $A$.

Let $x \in \partial \map G B$, where $\partial \map G B$ is the topological boundary of $\map G B$.

Then $x$ is not invertible in $A$.

## Pages in category "Element of Unital Banach Algebra on Boundary of Group of Units of Subalgebra is Not Invertible in Algebra"

The following 2 pages are in this category, out of 2 total.