title: Print all of the relations between a pair of sets
body: <p>Looking for some to help me out with my problem.
  I need to print all of the relations between a pair of sets with the domain and codomain input by the user.</p>
  
  <p>For example if the input was "ab" and "abc" the corresponding list of relations would be:</p>
  
  <pre><code>0: {}
  1: {(a, a), }
  2: {(a, b), }
  3: {(a, a), (a, b), }
  4: {(a, c), }
  5: {(a, a), (a, c), }
  6: {(a, b), (a, c), }
  7: {(a, a), (a, b), (a, c), }
  8: {(b, a), }
  9: {(a, a), (b, a), }
  10: {(a, b), (b, a), }
  11: {(a, a), (a, b), (b, a), }
  12: {(a, c), (b, a), }
  13: {(a, a), (a, c), (b, a), }
  14: {(a, b), (a, c), (b, a), }
  15: {(a, a), (a, b), (a, c), (b, a), }
  16: {(b, b), }
  17: {(a, a), (b, b), }
  18: {(a, b), (b, b), }
  19: {(a, a), (a, b), (b, b), }
  20: {(a, c), (b, b), }
  21: {(a, a), (a, c), (b, b), }
  22: {(a, b), (a, c), (b, b), }
  23: {(a, a), (a, b), (a, c), (b, b), }
  24: {(b, a), (b, b), }
  25: {(a, a), (b, a), (b, b), }
  26: {(a, b), (b, a), (b, b), }
  27: {(a, a), (a, b), (b, a), (b, b), }
  28: {(a, c), (b, a), (b, b), }
  29: {(a, a), (a, c), (b, a), (b, b), }
  30: {(a, b), (a, c), (b, a), (b, b), }
  31: {(a, a), (a, b), (a, c), (b, a), (b, b), }
  32: {(b, c), }
  33: {(a, a), (b, c), }
  34: {(a, b), (b, c), }
  35: {(a, a), (a, b), (b, c), }
  36: {(a, c), (b, c), }
  37: {(a, a), (a, c), (b, c), }
  38: {(a, b), (a, c), (b, c), }
  39: {(a, a), (a, b), (a, c), (b, c), }
  40: {(b, a), (b, c), }
  41: {(a, a), (b, a), (b, c), }
  42: {(a, b), (b, a), (b, c), }
  43: {(a, a), (a, b), (b, a), (b, c), }
  44: {(a, c), (b, a), (b, c), }
  45: {(a, a), (a, c), (b, a), (b, c), }
  46: {(a, b), (a, c), (b, a), (b, c), }
  47: {(a, a), (a, b), (a, c), (b, a), (b, c), }
  48: {(b, b), (b, c), }
  49: {(a, a), (b, b), (b, c), }
  50: {(a, b), (b, b), (b, c), }
  51: {(a, a), (a, b), (b, b), (b, c), }
  52: {(a, c), (b, b), (b, c), }
  53: {(a, a), (a, c), (b, b), (b, c), }
  54: {(a, b), (a, c), (b, b), (b, c), }
  55: {(a, a), (a, b), (a, c), (b, b), (b, c), }
  56: {(b, a), (b, b), (b, c), }
  57: {(a, a), (b, a), (b, b), (b, c), }
  58: {(a, b), (b, a), (b, b), (b, c), }
  59: {(a, a), (a, b), (b, a), (b, b), (b, c), }
  60: {(a, c), (b, a), (b, b), (b, c), }
  61: {(a, a), (a, c), (b, a), (b, b), (b, c), }
  62: {(a, b), (a, c), (b, a), (b, b), (b, c), }
  63: {(a, a), (a, b), (a, c), (b, a), (b, b), (b, c), }
  </code></pre>
  
  <p>The number of elements are calculated with formula:</p>
  
  <p>N_e = number of elements in final list;</p>
  
  <p>k and j = number of elements in given sets;</p>
  
  <p>N_e=2^{k*j}</p>