
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 sets $A = \{x \mid a-1 \leq x \leq 2a+3\}$ and $B = \{x \mid -1 \leq x \leq 4\}$ with the universal set $U = \mathbb{R}$:  
(1) When $a = 1$, find $(U \setminus A) \cap B$;  
(2) If $A \subseteq B$, determine the range of values for the real number $a$.

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