What is idempotent?

Answer 1

Idempotence refers to several definitions involving mathematical operations:

• A unary operation is idempotent if applying it twice gives the same result as applying it once. For example, multiplication by 1 is idempotent as a x 1 = a x 1 x 1 = a.
• Another definition of unary idempotence is that when the operation is applied twice, it returns the original number. An example of this is the use of binary encryption in onetime pads - adding 1 to a binary digit twice (and ignoring any other digits; i.e. modulo 2) returns the original digit.
• A binary operation is idempotent if for both of the operands, the result is the same, e.g. the maximum of the set (x, x) is x.