# cardinality

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## cardinality

(mathematics)
The number of elements in a set. If two sets have the same number of elements (i.e. there is a bijection between them) then they have the same cardinality. A cardinality is thus an isomorphism class in the category of sets.

aleph 0 is defined as the cardinality of the first infinite ordinal, omega (the number of natural numbers).

## cardinality

A quantity relationship between elements. For example, one-to-one, one-to-many and many-to-one express cardinality. See cardinal number.
References in periodicals archive ?
(a) An example top-k join query and the corresponding join cardinalities of join subspaces, and (b) estimates of the corresponding top-k candidate space.
If these cardinalities are equal then, by Theorem 2.16, [[DELTA].sub.[perpendicular to]] and [[DELTA]'.sub.[perpendicular to]] are isomorphic.
The value of [alpha]k computed by (31) is associated with the characteristics of image data sets, since its variation is caused by both the cardinalities of labeled samples in each category and the total samples.