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## #1 2010-04-19 03:34:23

amaryllis
Member
Registered: 2010-04-19
Posts: 1

### need help on cartesian products

Hello ppl!

i knw this question might be too easy for some of u bt im stuck!! i left maths for like 3 years now..and im back to it..

anyways, the question is this

for example:

an empty set multiply by {1, 3} is equals to empty set right??

if so.. then a power set of an empty set multiply by the same set is equals to empty set as well?

second example:

{(1, 2)} x {3, 4}

so this becomes... { ((1,2), 3) , ((1,2) , 4) ....} like this?

i hope my questions are clear

Last edited by amaryllis (2010-04-19 04:33:25)

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## #2 2010-04-19 09:14:11

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

### Re: need help on cartesian products

if so.. then a power set of an empty set multiply by the same set is equals to empty set as well?

These are not the same.

so this becomes... { ((1,2), 3) , ((1,2) , 4) ....} like this?

Yes.

"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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## #3 2010-04-19 14:09:49

Amarylli\$
Guest

### Re: need help on cartesian products

ohk..lemme get it straight... so the powerset of an empty set values are -> {{}, {}} and multipled lets say to {1}

so.. {{}, {}} x {1} = empty set?