Prove the power set of X exists

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Homework Statement



Let X be a set. Then the set

{Y:Y is a subset of X}

prove this is a set.Where do i start?

Really unsure, i know that i have to use the power set?

I have written down;

{0,1}^X
 
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undergraduate analysis.
I know how to prove basic things, like umm.
If f and g are both injective then so is g composed with f etc.
i want to say that it is a collection of unordered objects and is therefore a set. (Waste of words, i know)

It just seems WAY to abstract, the fact that {Y: Y is a subset of X} is a set of subsets of a set, surely proves that it is in fact a set! :(.
 
What formal definition of "set" are you told to use?
 
there is no formal definition, there is an informal definition that says that:

We define a set A to be any unordered collection of objects.