Prove cardinality of every finite nonempty set A is less then cardinality of natural number N(adsbygoogle = window.adsbygoogle || []).push({});

|A|<|N|

set A is nonempty finite set

natural number N is denumerable (infinite countable set)

|A|<|N| if there exist a injective (one-to-one) function f: A->N, but NO bijective function, which means NO surjective (onto) function

How to prove it in detail???

Help please!!!

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# Cardinality Problem: Prove |A| < |N|

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