def min_diff_pairs(nums):
  """
  Finds pairs of numbers in nums with the minimum absolute difference.
 
  Args:
      nums: A list of integers.
 
  Returns:
      A list of pairs of indices (i, j) for which nums[i] - nums[j] has the minimum
      absolute difference. The pairs are sorted first by i and then by j. Handles
      duplicate elements correctly.
  """
 
  sorted_nums = sorted(nums.copy())  # Sort a copy to avoid modifying original list
  min_diff = float('inf')
  result = []
  for i in range(len(sorted_nums) - 1):
    diff = abs(sorted_nums[i] - sorted_nums[i + 1])
    if diff < min_diff:
      min_diff = diff
      result = []
    if diff == min_diff:
      # Find all indices of sorted_nums[i] and sorted_nums[i+1] in the original list
      indices_i = [j for j, x in enumerate(nums) if x == sorted_nums[i]]
      indices_j = [j for j, x in enumerate(nums) if x == sorted_nums[i + 1]]
      # Create pairs of indices from the original list
      for ii in indices_i:
        for jj in indices_j:
          result.append((ii, jj) if ii < jj else (jj, ii)) 
 
  result.sort()  # Sort pairs first by i and then by j
  return result
 
# Example usage:
numbers = [4, 4, 2, 1, 3]
result = min_diff_pairs(numbers)
print(result)

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