
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
Among the following four propositions:  
① The graph of the function $y=(x+1)^2$ is translated by the vector $\overrightarrow{v}-(-1,0)$, and the corresponding function expression of the obtained graph is $y=x^2$;  
② Given plane vectors $\overrightarrow{a}=(\cos\alpha, \sin\alpha), \overrightarrow{b}=(\cos\beta, \sin\beta)$, if $\overrightarrow{a}=\lambda \overrightarrow{b}$, then the real number $\lambda=\pm1$;  
③ O is the centroid of $\triangle ABC$, then $\overrightarrow{OA}+ \overrightarrow{OB}+ \overrightarrow{OC}= \overrightarrow{0}$;  
④ Vectors $\overrightarrow{a}, \overrightarrow{b}, \overrightarrow{c}$ form equal angles pairwise, $|\overrightarrow{a}|=1, |\overrightarrow{b}|=2, |\overrightarrow{c}|=3$, then $|\overrightarrow{a}+ \overrightarrow{b}+ \overrightarrow{c}|=\sqrt{3}$.  
The numbers of the true propositions are __________.

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