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Topic: A size criterion: a question
Replies: 15   Last Post: Jan 9, 2013 1:22 PM

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Zaljohar@gmail.com

Posts: 2,665
Registered: 6/29/07
A size criterion: a question
Posted: Jan 6, 2013 2:35 PM
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If we characterize cardinality in the following manner, How much that
would differ from the known cardinality:

|x| < |y| iff there exist an injection from x to y and there do not
exist a surjection from a subset of x to y.

|x| > |y| iff there exist a surjection from a subset of x to y and
there do not exist an injection from x to y.

|x| = |y| iff there exist an injection from x to y and there exist a
surjection from a subset of x to y.

Zuhair



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