  Note that all of the polynomials \(p\)(x,y) in the above table, except for addition and subtraction, take values in \(\{0,1\}\) when the variables take values in \(\{0,1\}\). Such polynomials are called switching functions in computer science and electrical engineering, and as functions on \(\{0,1\}\) they are idempotent, that is, p\(^2 =\) p. The switching functions are exactly the idempotent polynomials in Boole’s algebra.