Re: Not sure about interpretation of this set notation

On Wed, 21 Dec 2005, Kenneth Bull wrote:

> X = { a /in B | a = 2k, k /in A }
>
> I am not sure about the k part. Does the above notation imply that
> "every k" in A must be considered (just like every a in B must be)?
>
The expression lacks coherence and should be stated as
X = { a in B | some k in A with a = 2k }
= { 2k in B | k in A }
= B /\ 2A
.