Thus the cardinal number of α is itself a class, and furthermore α is a member of it.
The cardinal number zero is the class of classes with no members; but there is only one such class, namely—the null class.
The Latin language often employed the ordinal number instead of the cardinal number.
The relation-number of a relation should be compared with the cardinal number of a class.
Thus the cardinal number one is the class of unit classes, the cardinal number two is the class of doublets, and so on.
In the above example 2R is an integral real number, which is distinct from a rational integer, and from a cardinal number.
What business has this cardinal number octiesque uno in a row of ordinals?
The notion of order, which is here introduced, is one which is not required in the theory of cardinal number.
Two equally numerous collections appear to have something in common: this something is supposed to be their cardinal number.
cardinal number A number, such as 3, 11, or 412, used in counting to indicate quantity but not order. Compare ordinal number. |