
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 following propositions:  
(1) If two planes are parallel, then a line in one of the planes must be parallel to the other plane;  
(2) If two planes are parallel, then a line perpendicular to one of the planes must also be perpendicular to the other plane;  
(3) If two planes are perpendicular, then a line perpendicular to one of the planes must be parallel to the other plane;  
(4) If two planes are perpendicular, then a line in one of the planes must be perpendicular to the other plane.  
The sequence numbers of all true propositions are __________.

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