1. The problem is unclear as the input is just the symbol \in, which is used in mathematics to denote "element of" in set theory. 2. Typically, \in is used to express that an element belongs to a set, for example, $x \in A$ means "x is an element of set A". 3. Since no specific problem or question is given, there is no equation or expression to solve or simplify. 4. If you have a specific question involving \in or set membership, please provide the full problem statement.