# Math Help - intro to schroder-bernstein

1. ## intro to schroder-bernstein

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2. Originally Posted by yellow4321
Let X,Y be finite sets with |X|=n and |Y|=m show n is 'less than or equal to m' then there is a injection X->Y.

note to moderators, this is not a case of double posting

3. Originally Posted by yellow4321
Let X,Y be finite sets with |X|=n and |Y|=m show n is 'less than or equal to m' then there is a injection X->Y.
The above is not the Schroeder-Bernstein Theorem.

It has a trivial proof that I gave in the other place you posted it.

4. Originally Posted by Plato
The above is not the Schroeder-Bernstein Theorem.

It has a trivial proof that I gave in the other place you posted it.
i don't think he/she meant to say that's the theorem. i think that's a part of the question and he/she wanted to use the theorem.

for those interested: Cantor–Bernstein–Schroeder theorem - Wikipedia, the free encyclopedia

could we even use the theorem here?

5. Originally Posted by Jhevon
i think that's a part of the question and he/she wanted to use the theorem.
But as the link you provided (BTW the wikapedia proofs are very poor) shows that the theorem does no apply in this case. S-B shows equality of cardinality. It is usually applies to infinite sets.