Given a sequence $\left\{ a _ { n } \right\}$, if we select the $i _ { 1 }$-th term, the $i _ { 2 }$-th term, $\cdots$, the $i _ { m }$-th term $\left( i _ { 1 } < i _ { 2 } < \cdots < i _ { m } \right)$, and if $a _ { i _ { 1 } } < a _ { i _ { 2 } } < \cdots < a _ { i _ { m } }$, then the new sequence $a _ { i _ { 1 } } , a _ { i _ { 2 } } , \cdots, a _ { i _ { m } }$ is called an increasing subsequence of length $m$ of $\left\{ a _ { n } \right\}$. By convention, any single term of the sequence $\left\{ a _ { n } \right\}$ is an increasing subsequence of length 1 of $\left\{ a _ { n } \right\}$. (I) Write out an increasing subsequence of length 4
Given a sequence $\left\{ a _ { n } \right\}$, if we select the $i _ { 1 }$-th term, the $i _ { 2 }$-th term, $\cdots$, the $i _ { m }$-th term $\left( i _ { 1 } < i _ { 2 } < \cdots < i _ { m } \right)$, and if $a _ { i _ { 1 } } < a _ { i _ { 2 } } < \cdots < a _ { i _ { m } }$, then the new sequence $a _ { i _ { 1 } } , a _ { i _ { 2 } } , \cdots, a _ { i _ { m } }$ is called an increasing subsequence of length $m$ of $\left\{ a _ { n } \right\}$. By convention, any single term of the sequence $\left\{ a _ { n } \right\}$ is an increasing subsequence of length 1 of $\left\{ a _ { n } \right\}$.
(I) Write out an increasing subsequence of length 4