Re: Are the following set operations true?

On 10 Dec 2005 19:47:12 -0800, "comtech" <comtech.usa@xxxxxxxxx>
wrote:

>Hi all,
>
>In my practice of set operations, I have summarized the following
>properties...
>
>Are these true?
>
>1.
>A in C,
>B in C,
>then
>
>(A intersect B) in C, (A union B) in C,
>
>
>2.
>
>1.
>C in A,
>C in B,
>then
>
>C in (A intersect B), C in (A union B),.
>
>
>3.
>
>(A intersect B) \ C = (A \ C) intersect (B \ C)
>
>(A union B) \ C = (A \ C) union (B \ C)
>
>C \ (A intersect B) = (C \ A) union (C \ B)
>
>C \ (A union B) = (C \ A) intersects (C \ B)
>
>Thanks a lot

You really shouldn't really need to ask these questions. First,
carefully read through any text that explains the concepts and shows a
few worked examples.

Then try the problems.

What's the point of having the proofs handed to you? How does that
build strength?

Try the problems and then show us your attempts at proofs or
disproofs. Don't rush it and write it up sloppily. Try to make the
argument both logically correct and also easy to understand. That
takes work, but in the struggle for clarity, your writing style will
improve over time.

Ok, here are some basic questions you should be able to answer before
even trying the problems.

If you are trying to prove a set inclusion, how do you start?

What about proving a set equality?

If one of the statements you are trying to prove about arbitrary sets
is actually false, what would it take to disprove it?

quasi
.

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