Countable Sets: Cantor's Theorem & Galileo's Paradox

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SUMMARY

There is no contradiction between Cantor's theorem regarding countably infinite power sets and Galileo's paradox. The discussion emphasizes that infinite sets should not be viewed as "huge" or "more" in a conventional sense, as these terms lead to confusion. Cardinality is the key measure for understanding infinite sets, where countable sets can be indexed by natural numbers, establishing a bijective correspondence between perfect squares and natural numbers.

PREREQUISITES
  • Understanding of Cantor's theorem
  • Familiarity with cardinality in set theory
  • Knowledge of bijective correspondence
  • Concept of countable and uncountable sets
NEXT STEPS
  • Research the implications of Cantor's theorem on set theory
  • Explore the concept of cardinality in greater depth
  • Study bijective functions and their applications in mathematics
  • Investigate other paradoxes related to infinite sets, such as Russell's paradox
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Mathematicians, educators, and students interested in set theory, particularly those exploring concepts of infinity and cardinality.

Hippasos
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Hi!

Can You please confirm that there is no contradiction between Cantor's theorem of countably infinite power sets and Galileo's paradox?

- Thanks
 
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Don't think of infinite sets as something "huge", and don't think of different countable sets as "equally huge", because it will only cause confusion. There are not "more" integers than perfect squares, because "more" doesn't make sense when it comes to infinite sets, unless you define what you mean by "more".

We use cardinality as one type of measure of infinite sets. Countable sets are simply sets that can be indexed by the natural numbers, that is: put in a bijective correspondence with the set of natural numbers. In this context there are "equally many" perfect squares as natural numbers, simply because they can be put in a bijective correspondence.
 

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