{ 1 , 2 , 3 }                  # == {1,2,3}
{ 1 , 2 , 3 , 2 , 1}           # == {1,2,3}
inter( {1,2} , {1,3} )         # == {1}
inter( union({1,2},{1,3}) , {3,4,5} )  # == {3}
union( {1,2}, inter({1,3} , {3,4,5}))  # == {1,2,3}
diff( {0,1,2,3,4,5} , {1,3,5}) # == {0,2,4}
S_2 = {1,2,4,8,16,32,64,128}   # == ca depend des bornes
S_2                            #
inter(S_2 , comp(S_2))         # == {} quelque soit S_2
union(S_2 , comp(S_2))         # == All elem
S_3 = S_2                      #
union( {1}, {1,2}, {2,3})      # union a n arguments =={1,2,3}
{1,}                  # Error
S_111                 # Error
diff({})              # Error
comp({)}              # Error
{1}                   # verif resynchro apres erreur == {1}