
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given two lines $l_{1}：mx+8y+n=0\text{ and }l_{2}：2x+my-1+ \frac {n}{2}=0$. Determine the values or value ranges of $m$ and $n$ such that:
   (I) $l_{1} \perp l_{2}$;
   (II) $l_{1} \parallel l_{2}$.

Present the answer in LaTex format: \boxed{Your answer}
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