\[
\text { Let } \begin{aligned}
U & =\{1,2,3, \cdots\} \\
A & =\{1,2,3, \cdots, 26\}
\end{aligned}
\]
VHL Central I Voc...
Use the roster method to write the set $A^{\prime}$.
\[
A^{\prime}=
\]
(Use a comma to separate answers as needed. Use ascending order.)
Answer
\( \boxed{\text{Therefore, the final answer is undefined.}} \)
Step 1 ：Let \( U = \{1,2,3, \cdots\} \) and \( A = \{1,2,3, \cdots, 26\} \).
Step 2 ：Use the roster method to write the set \( A^\prime \).
Step 3 ：Without a clear definition of the universal set \( U \), we cannot determine the exact elements of \( A^\prime \).
Step 4 ：If we assume that \( U \) contains all natural numbers, then \( A^\prime \) would contain all natural numbers greater than 26. But this is just an assumption.
Step 5 ：\( \boxed{\text{Therefore, the final answer is undefined.}} \)
