
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
Define an even function $f(x)$ on **R** that satisfies: for any $x_1$, $x_2 \in (-\infty, 0)$ ($x_1 \neq x_2$), it holds that $f(x_1) > f(x_2)$. Then, arrange $f(-2)$, $f(1)$, and $f(3)$ in ascending order.

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