can anyone do this question

The sets A, B and C are given by

A = {1, 2, 3, 4},

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- November 17th 2008, 09:56 AMsrk619logicsets
can anyone do this question

The sets A, B and C are given by

A = {1, 2, 3, 4}, - November 17th 2008, 10:18 AMclic-clac
A diagram is easy but with a pen :)

Let see**b)**

and , so is surjective. But since has more elements than , can't be injective, so can't be bijective.

and , so is surjective. But since has more elements than , can't be injective, so can't be bijective. (yeah the proof is quite similar)

is the identity map on , it is bijective (i.e. injective and surjective).

That means is not injective. Furthermore, as has more elements than , so is not surjective, in conclusion, is "none of these".