Definition:Bound Occurrence

Definition
Let $\mathcal L_1$ be the formal language of predicate calculus.

Let $\mathbf A$ be a WFF of $\mathcal L_1$.

Let $Q x$ be an occurrence of a quantifier in $\mathbf A$.

Any occurrence of the variable $x$ in the scope of $Q$ is called a bound occurrence.

A variable which occurs as a bound occurrence is called a bound variable or dummy variable.

Also see

 * Occurrence
 * Free Occurrence, the complementary notion
 * Alphabetic Substitution