Definition:Precisely One Function

Definition
Let $p_1, p_2, \ldots, p_n$ be statements.

The precisely one function is the propositional function $\map P {p_1, p_2, \ldots, p_n}$ defined as:
 * $\map P {p_1, p_2, \ldots, p_n}$ is true precisely one of $p_1, p_2, \ldots, p_n$ is true.