# Thread: Argument #4, determine validity.

1. ## Argument #4, determine validity.

This is the one I am having the most trouble with, thanks in advance.

Determine, by any means, whether the following argument is valid or not:

"If a set A is a proper subset of another set B, then the intersection of A and B is also a proper subset of B; but A is equal to B or B is a proper subset of A; hence the intersection of A and B is a proper subset of A."

Before I try using LaTex to start the problem, is the file really a whole gig...heh.

2. A = (1,2,3,4) B = (2,3,4,1)

A ^ B = (1,2,3,4) = A = B...

valid?

3. In your example, the intersection of A and B is not a proper subset of A.

Note that set elements should be written between curly braces, not parentheses.

4. Like I said before I am pretty lost, any help would be appreciated.

My parentheses was meant to represent the squiggly lines, btw.

5. but A is equal to B or B is a proper subset of A
In your example, this is true.

hence the intersection of A and B is a proper subset of A
And this is false in your example.

My parentheses was meant to represent the squiggly lines, btw.
Then why not use { and } keys?