Enter the elements of the following subsets of N:
{x; x7 ∧ x 13}
My answear is {x; x7 ∧ x 13} = (13, ∞)

Is that answear correct? or how should I think?

Question

Enter the elements of the following subsets of N:
{x; x>7 ∧ x >13}
My answear is {x; x>7 ∧ x >13} = (13, ∞)

Is that answear correct? or how should I think?

welshfella · Answer

you are right values of x between 7 and 13 are not included because of the intersect symbol.

zzr0ck3r · Answer

But you wrote an interval, and it wants the elements in N.

So we would list it like, $$\{13,14,15,16,...\}$$

or 

$$\mathbb{N}-\{1,2,3,4,5,6,7,8,9,10,11,12,13\}$$

zzr0ck3r · Answer

interval notation implies continuum

zzr0ck3r · Answer

I think...

zzr0ck3r · Answer

or better $\mathbb{N}\cap (13, \infty)$

^^^thats the one

welshfella · Answer

yep  I missed that

zzr0ck3r · Answer

I was thinking it would be ok if you used an interval as long as we said our universal set was the natural numbers, but I dont think that makes sense because the natural numbers do not form a system, not even a group.

Maybe just make our own notation

$$\mathbb{N}\cap (13, \infty)=(13,\infty)_{\mathbb{N}}$$   :)