Give a natural example of nonempty sets with a common binary operation * where both X and Y have identity elements, but they are not the same.
Umm... I can't really think of anything, every set of integer mod would have 1 as identity...
Give a natural example of nonempty sets with a common binary operation * where both X and Y have identity elements, but they are not the same.
Umm... I can't really think of anything, every set of integer mod would have 1 as identity...