How can you merge arrays in PHP while maintaining references to elements from one array in another?

When merging arrays in PHP using functions like `array_merge`, the resulting array will not maintain references to elements from the original arrays. To merge arrays while preserving references, you can use the `+` operator or `array_merge_recursive` function. The `+` operator will preserve keys and values from the first array when there are duplicate keys, while `array_merge_recursive` will recursively merge arrays and maintain references.

// Using the + operator to merge arrays while maintaining references
$array1 = ['a' => 1, 'b' => 2];
$array2 = ['b' => 3, 'c' => 4];

$result = $array1 + $array2;

print_r($result);