are (A u B) and (A U B) different? if so, how?

Question

usukidoll · Answer

(A U B)  means the union of A and B 
ex. A = 1,2,3
B = 4,5,6
A U B = 1,2,3,4,5,6

usukidoll · Answer

taking the intersection $$A \cap B = \emptyset $$ because in my example there is no element in common

rebeccaxhawaii · Answer

union meaning "or"?

zepdrix · Answer

Yes,
union means "or"
intersection means "and"
:)

rebeccaxhawaii · Answer

so (A u B) and (A U B) are the same thing? my teacher is saying they are different.

usukidoll · Answer

how is your teacher saying that it's different? that notation A u B ... I haven't seen it before
This -> A U B was seen many times in my Discrete math book and my Intro to Advanced Mathematics Book

rebeccaxhawaii · Answer

hmm okay thanks

usukidoll · Answer

P.S> I sound like a zombie.... real analysis practice blahhhhhhhhhh

mjdennis · Answer

I'm curious...  the operation "U" in the expression "(A U B)" is called the union.  Did your teacher give a name for the operation "u" in "(A u B)"