A boolean domain B {\displaystyle \mathbb {B} } is a generic 2-element set, say, B = { 0 , 1 } {\displaystyle \mathbb {B} =\{0,1\}} , whose elements are interpreted as logical values, typically, 0 = f a l s e {\displaystyle 0=\mathrm {false} } and 1 = t r u e {\displaystyle 1=\mathrm {true} } .
A boolean variable x {\displaystyle x} is a variable that takes its value from a boolean domain, as x ∈ B {\displaystyle x\in \mathbb {B} } .
