Let $a=1+10^{-4}$. Consider some $2023\times 2023$ matrix with each entry a real in $[1,a]$. Let $x_i$ be the sum of the elements of the $i$-th row and $y_i$ be the sum of the elements of the $i$-th column for each integer $i\in [1,n]$. Find the maximum possible value of $\dfrac{y_1y_2\cdots y_{2023}}{x_1x_2\cdots x_{2023}}$ (the answer may be expressed in terms of $a$).
1. Let \( A \) be a \( 2023 \times 2023 \) matrix with each entry \( a_{ij} \) such that \( 1 \leq a_{ij} \leq a \), where \( a = 1 + 10^{-4} \).

2. Define \( x_i \) as the sum of the elements in the \( i \)-th row:
   \[
   x_i = \sum_{j=1}^{2023} a_{ij}
   \]
   Similarly, define \( y_i \) as the sum of the elements in the \( i \)-th column:
   \[
   y_i = \sum_{j=1}^{2023} a_{ji}
   \]

3. We need to find the maximum possible value of the ratio:
   \[
   \frac{y_1 y_2 \cdots y_{2023}}{x_1 x_2 \cdots x_{2023}}
   \]

4. Note that the sum of all elements in the matrix is the same whether summed by rows or by columns:
   \[
   \sum_{i=1}^{2023} x_i = \sum_{i=1}^{2023} y_i
   \]

5. Each \( x_i \) and \( y_i \) is a sum of 2023 terms, each between 1 and \( a \). The maximum value of \( x_i \) or \( y_i \) occurs when all terms are \( a \):
   \[
   x_i \leq 2023a \quad \text{and} \quad y_i \leq 2023a
   \]

6. To maximize the ratio \( \frac{y_1 y_2 \cdots y_{2023}}{x_1 x_2 \cdots x_{2023}} \), we need to consider the product of the sums. The product of the sums of the columns and rows will be maximized when the sums are as large as possible.

7. If we set each \( a_{ij} \) to be either 1 or \( a \), we can balance the sums to achieve the maximum product. For simplicity, assume half the entries in each row and column are 1 and the other half are \( a \).

8. Let \( k \) be the number of entries in each row and column that are \( a \). Then:
   \[
   k + (2023 - k) = 2023
   \]
   \[
   x_i = k \cdot a + (2023 - k) \cdot 1 = k(a - 1) + 2023
   \]

9. To maximize the product, we set \( k \) such that \( k(a - 1) \) is maximized. Since \( a = 1 + 10^{-4} \), \( a - 1 = 10^{-4} \).

10. The optimal \( k \) is approximately half of 2023, but for simplicity, assume \( k = 1011 \) and \( 2023 - k = 1012 \):
    \[
    x_i = 1011 \cdot a + 1012
    \]

11. Therefore, each \( x_i \) and \( y_i \) is approximately:
    \[
    x_i = y_i = 1011a + 1012
    \]

12. The product of all \( x_i \) and \( y_i \) is:
    \[
    x_1 x_2 \cdots x_{2023} = (1011a + 1012)^{2023}
    \]
    \[
    y_1 y_2 \cdots y_{2023} = (1011a + 1012)^{2023}
    \]

13. The ratio is:
    \[
    \frac{y_1 y_2 \cdots y_{2023}}{x_1 x_2 \cdots x_{2023}} = \frac{(1011a + 1012)^{2023}}{(1011a + 1012)^{2023}} = 1
    \]

The final answer is \(\boxed{1}\).