= Evaluation character
{title2=$\delta_x$}
For an <algebra> $A$ of complex-valued <functions> on a <set>, evaluation at $x$ is the multiplicative <linear functional> $\delta_x(f)=f(x)$. It is an <algebra character> precisely when it is nonzero, meaning that some $f\in A$ has $f(x)\ne0$. This holds automatically if $A$ contains the constant function one.
The nonzero requirement matters for algebras with a common zero: evaluating $\{f\in C[0,1]:f(0)=0\}$ at zero gives the zero <linear functional>, which is not an <algebra character>.
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