Is DFA and Regular Expression equivalent? The language of a DFA can be the empty set (by defining no final states), but can a Regular Expression do that? 

If Regular Expression cannot do that, does it mean that DFA and Regular Expression are not equivalent (in at least some cases)?
According to Wikipedia:

Given a finite alphabet $\Sigma$, the following constants are defined as regular expressions:

(empty set) $\emptyset$ denoting the set $\emptyset$.

...



... a string that contains only an empty-set symbol is a regular expression, which represents the empty language.