NOR is a functionally complete operator, meaning all other logical operations can be expressed using only NOR. To express NOT using NOR, one can use the expression NOT(x) = x NOR x. By applying DeMorgan's laws, AND and OR can be derived as follows: AND(x, y) = NOT(x NOR y) and OR(x, y) = NOT(x) NOR NOT(y). This demonstrates that NOR can replicate the functionality of NOT, AND, and OR, confirming its completeness in logical operations. The discussion emphasizes the ability to construct all basic logical functions solely with the NOR operator.