Balanced Boolean function
= Balanced Boolean function
{title2=$|f^{-1}(0)|=|f^{-1}(1)|$}
A <Boolean function> on a finite nonempty domain is balanced when it is zero on exactly half the inputs and one on the other half. For a one-<bit> domain, the balanced functions are $f(x)=x$ and $f(x)=1⊕x$, while the remaining two functions are <constant functions>. The <Deutsch algorithm> distinguishes these two classes with one <Boolean quantum oracle> query in the absence of noise.