Question

[Set Theory] Write the following set in the form {x| P(x)}

Answer 1

In this case, does P(x) refer to the power set or not?

Answer 2

The set is: {4, 9, 16, 25...}

This obviously has something to do with x^2

Answer 3

I am new to set theory. Can it be something like {x| x>1, x^2}

Answer 4

Yes, P(S) is the power set.

Answer 5

so I'm wrong then?

Answer 6

with my answer

Answer 7

It's been a while since I did any set theory... Not sure if I can even be of any help, but going to try to do some research.

Answer 8

ok, I understand. Thanks anyway

Answer 9

Actually, I'm pretty sure that your answer is correct - P(x) might be some function, in your case - x^2. But ask someone else as well, to make sure.
@dan815

Answer 10

Oh and by the way, the power set is P(S) - a set of all subsets of S, so if you had:
S={1,2,3}
P(S) = {{}, {1}, {2}, {3}, {1,2}, {2,3}, {1,3}, {1,2,3}}

Answer 11

So that kinda seems irrelevant to what you're being asked to do.

Answer 12

I thought it may have been refering to some function. I just thoguth ti was a little strange that my lecturer chose to use P instead of the classical f to represent this.

Answer 13

It seems strange that he would use notation which actually conflicts with another form of notation though. I doubt he would have made a mistake but then again if it is in fact meant to mean power set, I cannot figure out how to work this out. :/

Answer 14

ya its just a set of n^2 n>0, n E Z+

Answer 15

or just n E z

Answer 16

oh yeah, it can be either positive or negative.

It cannot be 1 though so would the final answer be:

{x^2|2<=x<=2, xEZ}

?

Answer 17

messed up the inequality there... 1 sec...

Answer 18

x<=-2, x>=2, xEZ

Answer 19

yes