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Can a Finite Set Be Equivalent to Its Proper Subset?
publish date: 2026/05/23 21:45:34.199974 UTC
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True or False: A finite set can be equivalent to one of its proper subsets.
Correct Answer
False
Explanation
False. A finite set with \(n\) elements cannot be put into bijection with any proper subset (which has at most \(n-1\) elements). This is not just obvious — it requires proof — but the result holds rigorously. The fact that infinite sets can match their proper subsets is precisely what distinguishes them from finite sets and makes the concept of infinity so counterintuitive.
Reference
Introduction to Differential Calculus (Systematic Studies with Engineering Applications for Beginners) - 2012
