Sets?

[Freeman]

I have a question, I forget what the symbol is for this set problem: {1,2,3,4,5,6,7,8,9,10} ??? {4,6,8,9,10}= {1,2,3,5,7} What is it???

[bloodhound]

that set operation is \

 

and is defined as

 

[A \ B:={x:x in A and x not in B}

[Dave]

or, typeset in lovely latexy goodness:

 

[math]A \;\backslash\; B = \{ x\: | \: x \in A, x\notin B \}[/math]

[Freeman]

How would I write this in mathematica code???

The equation: [math] A\:\backslash\; B = \{x\: l \:x \in A, x\notin B \} [/math]

Where A is the set of all whole postive integers, and B is the set of [math] ^c\{D \times E\}_{D,E=2}[/math]

[bloodhound]

got no idea what u mean by B

[e(ho0n3]

The other symbol you can use is "-", e.g. A - B. I don't know which one is more standard though. Personally, I like "-" better.

[bloodhound]

well. \ is used in our uni course

[ed84c]

can somebody tell me what a 'set' is?

[e(ho0n3]

Maybe this link will help: http://mathworld.wolfram.com/Set.html

[Freeman]

That is good, but it doesn't give codes for anything!!!

[Dave]

[math'] ^c\{D \times E\}_{D,E=2}[/math]

 

This makes absolutely no mathematical sense.

[bloodhound]

im completely baffled as well. can u explain what u meant by that Freeman

[bloodhound]

unless , its his new twisted way of writing the set {4}

[Dave]

But why would you have that complement thing? That's just silly.

[bloodhound]

maybe he has discovered some interesting property about [math]\mathbb{C}[/math]\{4}

 

that noone knows about

[Freeman]

No, what I mean is the limit to the set {LxM} is c, L is at least 2 and so is M. The set of every solution of this is the set I was trying to write...

[Dave]

Okay, firstly something you should know in regards to set theory notation:

 

Firstly, most sets are defined using uppercase letters. Secondly, the operation A x B where A and B are sets is defined as the cartesian product of a set, notably:

 

[math]A \times B = \{ (a,b) \: | \: a \in A, b \in B \}[/math]

 

The proper mathematical way of defining your set is as follows:

 

[math]S = \{ (l, m) \: | \: l, m \in \mathbb{R}, l, m \geq 2\}[/math]

 

Unless, of course, I've made a mistake.

[bloodhound]

I am still confused by the meaning of ordered pair (a,b)

[Dave]

http://www.math.com/school/glossary/defs/ordered_pair.html

[Freeman]

Thanks Dave!

 

Where is the mathematica code manual? How would I put this into mathematica???

 

Thanks a lot Dave!

[Dave]

Huh? How would putting this set into mathematica help with anything in the slightest?

[bloodhound]

what are u trying to do with it anyway?

[Dave]

I think if we knew what the problem was, then we'd be able to help a bit.