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Some help on sets, please!by hikki_pop
Tags: sets 
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#1
Jun1504, 04:58 AM

P: 17

can anyone tell me the answer to this??
if U (universal set) = {1,2,3,4,5,6,7,8,9,10,11,12,13,14} C (just a simple subset of the universal set U)= {1,2,3,4,5} then what would be the answer if: C U U' ????? (subset C union universal set complement) thanks !! sorry for the double post!! please delete this one!!! 


#2
Jun1704, 11:06 PM

P: 418

Don't you need to also include your universe of discourse?
If your universe of discourse is the natural numbers then,... C U U' would be {1,2,3,4,5} U {15,16,17,...} If your universe of discourse is the integers then,... C U U' would be {... 3,2,1,0} U {1,2,3,4,5} U {15,16,17,...} For other universes of discourse it could get ugly. :surprise: Edited to add the following possibility,... If your universe of discourse is U then U' is the empty set so,... C U U' would be just be {1,2,3,4,5} 


#3
Jun2004, 07:03 PM

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P: 39,497

Neutron star: the original post said "U (universal set) = 1,2,3,4,5,6,7,8,9,10,11,12,13,14}.
That is the "unverse of discourse". 


#4
Jun2004, 08:04 PM

P: 418

Some help on sets, please!
I would agree that they are technically incorrect in doing this. But they seem to do it quite often just the same. I've actually confronted a college professor about this once and all I got in return was a lecture on the difference between a universal set and the universe of discourse. Don't look at me. I'm with you! As far as I'm concerned professors and authors who think there is a difference are wrong. But since its an imperfect universe (no pun intended) I like to cover all my bases. 


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