Let \[ \begin{array}{l} U=\{1,2,3,4,5,6,7\} \\ A=\{4,5,6,7\} \end{array} \] List the members of each set, using set braces. \[ A^{\prime}=\{\} \] (Use a comma to separate answers as needed.)

Step 1 ：Let the universal set U be \(U=\{1,2,3,4,5,6,7\}\) and the set A be \(A=\{4,5,6,7\}\).

Step 2 ：The complement of set A in the universal set U, denoted as \(A'\), is the set of all elements in U that are not in A.

Step 3 ：So, we need to find all the elements in U that are not in A.

Step 4 ：The elements in U that are not in A are \(1, 2, 3\).

Step 5 ：Therefore, the members of the set \(A'\) are \(\boxed{1, 2, 3}\).