Cardinality Question from Basic Analysis. Thanks for any help.

In summary, the conversation discusses the task of proving that the cardinality of the union of two sets, A and B, is less than or equal to the cardinality of the real numbers. The person seeking help has limited knowledge and is unsure of how to approach the problem. They mention having 1-1 functions from A and B to the real numbers, but they are not familiar with the arithmetic of cardinal numbers.
  • #1
snowfox2004
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Homework Statement


If the cardinality of A is less than or equal to the cardinality of the reals and the cardinality of B is less than or equal to the cardinality of the reals, I need to show that the cardinality of the union of A and B is less than or equal to the cardinality of the reals.

IE: Prove that if |A|</=|R| and |B|</=|R|, then |AUB|</=|R|.

Thanks for any help. I am in a basic analysis class, and we just started a small section on cardinality.


Homework Equations





The Attempt at a Solution


All I know is that based on my assumption, I know that there is a 1-1 function from A to the real numbers and another 1-1 function from B to the real numbers.
 
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  • #2
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Nope, sorry.
 

1. What is cardinality in basic analysis?

Cardinality refers to the number of elements in a set. It is a measure of the size of a set, and can be finite or infinite.

2. How is cardinality represented?

In basic analysis, cardinality is typically represented by the symbol "|" or "||" surrounding the set. For example, if a set A has 5 elements, its cardinality would be written as |A| = 5.

3. What is the difference between finite and infinite cardinality?

Finite cardinality refers to the number of elements in a set that can be counted and is represented by a whole number. Infinite cardinality, on the other hand, refers to the number of elements in a set that cannot be counted and is represented by the symbol "∞".

4. How is cardinality related to the concept of subsets?

Cardinality is related to the concept of subsets in that the cardinality of a subset is always less than or equal to the cardinality of the original set. This means that a subset cannot have more elements than the original set.

5. Can two sets have the same cardinality?

Yes, two sets can have the same cardinality if they have an equal number of elements. This is known as having a one-to-one correspondence between the elements of the two sets.

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