Show and test the empty set...
Empty = {---  } has 0 elements.
The set is empty

S1 = {  1  } has 1 elements.
Set S1 is *not* empty

{  0  } union {---  } = {  0  }

{  0  1  } union {  2  3  } = {  0  1  2  3  }

{  0  1  3  } union {  0  2  3  } = {  0  1  2  3  }

Intersection of {  0  1  3  } and {  3  } is: {  3  }

Relative complement of {  0  1  2  3  }and {  0  } is: {  1  2  3  }

Symmetric difference of {  0  2  3  } and {  0  1  3  } is: {  1  2  }

Set A: {  0  1  3  }
Set B: {  0  2  3  }
Set A is not equal to set B