Yes, the set <span>of people who wear expensive perfume is well-defined.</span><span> A set is said to be well-defined if its definition assigns it a unique value. Otherwise, the set is said to be not well-defined or ambiguous."W</span><span><span>ell-defined” means that any given object in the entire world, whether abstract or concrete is either an element of the set or isn't.</span> </span>