
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 the sets $A=\{x \mid 2-a \leq x \leq 2+a\}$ and $B=\{x \mid x \leq 1 \text{ or } x \geq 4\}$.
(1) When $a=3$, find $A \cap B$.
(2) If $a > 0$ and $A \cap B = \emptyset$, find the range of the real number $a$.

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