A unate function is a type of boolean function which has monotonic properties.
They have been studied extensively in switching theory.

A function is said to be positive unate in
if for all ,
Likewise, it is negative unate in if
If for every f is either positive or negative unate in the variable then it is said to be unate. A function is binate if it is not unate.

For example the Logical disjunction

Logical disjunction

In logic and mathematics, a two-place logical connective or, is a logical disjunction, also known as inclusive disjunction or alternation, that results in true whenever one or more of its operands are true. E.g. in this context, "A or B" is true if A is true, or if B is true, or if both A and B are...

function or with boolean values are used for true (1) and false (0) is positive unate.