Changes

An important concept in set theory is [[cardinality]]. In the case of finite sets, this is simply the number of elements of the set. So {1,2} has a cardinality of 2. However, the theory is more complicated in the case of infinite sets.   

An important concept in set theory is [[cardinality]]. In the case of finite sets, this is simply the number of elements of the set. So {1,2} has a cardinality of 2. However, the theory is more complicated in the case of infinite sets.   

It was thought that an informal concept of sets ([[Naive set theory]]) was sufficient, however [[Bertrand Russell's]] shows that this can lead to a contradiction, if sets are allowed to contain themselves. Modern set theory is more formal, and disallows such paradoxical sets.

It was thought that an informal concept of sets ([[Naive set theory]]) was sufficient, however [[Russell's Paradox]] shows that this can lead to a contradiction, if sets are allowed to contain themselves. Modern set theory is more formal, and disallows such paradoxical sets.

[[Category:Mathematics]]

[[Category:Mathematics]]