Does the term Equipollent simply mean bijective?
I have seen that by definition a mapping is equipollent iff it is bijective. What is the point of such a statement?
Context: It will be used in Zorichs's Mathematical Analysis I to define cardinality of a set. (p25)
Two sets are said to be equipollent if there is a bijective function mapping one onto the other.
"Equipollent" means "of equal power", where "power" here alludes to the size of the sets. Two sets are equipollent precisely if they have the same cardinality.