Definition:Bound Variable/Predicate Logic

Definition
In predicate logic, a bound variable is a variable which exists in a WFF only as bound occurrences.

Also known as
A bound variable is also popularly seen with the name dummy variable. Both terms can be seen on.

In treatments of pure logic, this is sometimes known as an individual variable.

Some sources call it an apparent variable, reflecting the fact that it only "appears" to be a variable.

Some authors gloss over the difference between:
 * a bound variable: a variable which exists in a WFF only as bound occurrences

and:
 * a bound occurrence of a variable which may otherwise exist as a free occurrence

Also see

 * Definition:Bound Occurrence


 * Definition:Bound Variable


 * Definition:Free Variable