Boolean logic

Variable

A named place whose value is supplied by an assignment or binder.

Definition

Variable

A variable stands for a value drawn from a declared set or sort.

Boolean variables range over true and false. SMT variables may instead range over integers, real numbers, bit-vectors, strings, or other sorts.

01

Example

In x + 2 = 5, x is a variable whose satisfying integer value is 3.

02

Important distinction

A program variable can change during execution. A logical variable denotes a value within one interpretation unless the formal model represents time explicitly.

After reading this article, you should be able to

  • Define Variable in the sense used on this site.
  • Identify a variable's allowed values from its declared sort.