
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 "a > b" is a sufficient but not necessary condition for "a<sup>2</sup> > b<sup>2</sup>";  
② "lga = lgb" is a necessary but not sufficient condition for "a = b";  
③ If x, y ∈ R, then "|x| = |y|" is a necessary and sufficient condition for "x<sup>2</sup> = y<sup>2</sup>";  
④ In △ABC, "sinA > sinB" is a necessary and sufficient condition for "A > B".  
Among these propositions, the true ones are. (Write down the numbers of all true propositions)

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