We have seen several special symbols that are useful when making mathematical statements.

The universal quantifier $$

can be read as "for all" or "for any".

The existential quantifier $$

can be read as "there exists" or "for some".

The implication symbol $$

can be read as "implies" or "only if$".$

The reverse implication symbol $$

can be read as $"$is implied by$"$ or $"$if$".$

The double implication symbol $$

can be read as $"$is equivalent to$"$ or $"$if and only if$".$