Cardinalities of Infinite Sets: Proving Bijective Relationship (0,1) and (0,2)

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The discussion centers on proving that the open intervals (0,1) and (0,2) have the same cardinality by establishing a bijective function, specifically f(x) = 2x. It is clarified that the concept of cardinality applies to both finite and infinite sets, allowing for the conclusion that these two infinite sets are numerically equivalent. The initial confusion regarding the application of cardinality to infinite sets is resolved, affirming that bijective relationships indicate equal cardinality regardless of finiteness. The participants confirm the correctness of the proof and celebrate the resolution of the problem. This highlights the importance of understanding cardinality in the context of infinite sets.
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Homework Statement


Explain why ## (0,1 ) ## and ## (0,2)##

I have proved that a function ## f: (0,1 ) -> (0,2) ##defined by f(x) =2x is bijective.

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The Attempt at a Solution


I could state that due to the sets relationship being bijective they have the same cardinality, but this is only true if both sets are finite. Here, (0,1) and (0,2 ) are infinite.

Any help?
 
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What is your definition of "having the same cardinality"?
 
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Nevermind, you are right. The definition of same cardinality or numerically equivalency doesn't restrict finite from infinite sets.
 
knowLittle said:
Nevermind, you are right. The definition of same cardinality or numerically equivalency doesn't restrict finite from infinite sets.

Right! So you solved the problem correctly. Congratz!
 
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