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A comment on Why Don't Computer Scientists Learn Math?. Parent comment

Re:Why Don't Computer Scientists Learn Math? by berbc on Saturday November 19, 2016 @10:51AM (#12993962)
If by [1..N ⟶ 1..N] you mean the set of functions from [1..N] that have values in [1..N], I think you are wrong. The formula in the post describes a subset, the set of such functions that are surjective.
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Re:Why Don't Computer Scientists Learn Math? by j-pb on Saturday November 19, 2016 @11:14AM (#12994081)
Yeah I think your right, in this context I saw the case of [ A -> B ] as a function from coimage A to image B which are all bijective. But it is meant as the more standard domain A to codomain B.

His natural language description is somewhat lacking in that aspect

> I had already explained that [1..N ⟶ 1..N] is the set of functions that map the set 1..N of integers from 1 through N into itself,

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Re:Why Don't Computer Scientists Learn Math? by sampo on Saturday November 19, 2016 @09:37PM (#12996960)
Well, he did say "into itself", not "onto itself".
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