
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
In space, ① if four points are not coplanar, then any three of these points are not collinear; ② if two lines do not have a common point, then these two lines are skew lines. Among the above two propositions, the ones whose converse propositions are true are __________. (Fill in the serial numbers of the propositions that meet the requirements)

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