Question

What is Idempotent law?

Answer 1

Idempotence:

Idempotence is the property of certain operations in mathematics that can be applied multiple times without changing the result.

Idempotent law for a set:

Intersection and union of any set with itself revert the same set.

For a random set $A$:

$A\cup A=A$ and $A\cap A=A$