
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 four points in space are coplanar, then there must be three points that are collinear; ② If four points in space are not coplanar, then any three points among them are not collinear; ③ If among four points in space, three points are collinear, then these four points are coplanar; ④ If among four points in space, any three points are not collinear, then these four points are not coplanar. Among these propositions, the correct ones are __________. (Fill in the serial number)

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