First ,what do you mean by ?? The subset of the reals (or complex) with those two elements? If so zero cannot be anything there since it doesn't belong to the set!
Also, the product of isn't defined: ...!!
If this is so the above isn't a group.
But perhaps you meant the open interval which, by some misterious reason, you denote by ...(!)
Then you must show
, and this last inequality is obviously true.