Another Axiom of Separation Qns

Let be a formula of the languages of set theory. Let X be a set. Then the following is a set: , ie all the elements of X with the property form a set.

Write down a formula saying that "v is a set which has exactly three elements".

I would like to check whether it is possible to represent the above statement as this:

Thanks in advance.

Re: Another Axiom of Separation Qns

No, that only says that v has at least 1 element and at most 3 elements. You need to include formulation that x, y, and z are different from one another.

Also, you're missing a right parenthesis on the end.

Re: Another Axiom of Separation Qns

Quote:

Originally Posted by

**MoeBlee** No, that only says that v has at least 1 element and at most 3 elements. You need to include formulation that x, y, and z are different from one another.

Also, you're missing a right parenthesis on the end.

Hey,

Can I write

?

Thanks in advance.

Re: Another Axiom of Separation Qns

Now you've only said that v has at least two elements and at most three elements. But you're getting close.

Re: Another Axiom of Separation Qns

Hey,

Am I right to represent it as such:

?

Thanks in advance.

Re: Another Axiom of Separation Qns