Can you please check if they are correct?

a. {0} <-- True

b. { ,{0}} <-- True

c. { } { } <-- True

d. { } {{ }} <-- False

e. { } { , { }} <-- True

f. {{ }} { ,{ }} <--False

g. {{ }} {{ },{ }} <--False

Thank you

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- Sep 18th 2009, 09:09 PMzpwnchenquick question about set
Can you please check if they are correct?

a. {0} <-- True

b. { ,{0}} <-- True

c. { } { } <-- True

d. { } {{ }} <-- False

e. { } { , { }} <-- True

f. {{ }} { ,{ }} <--False

g. {{ }} {{ },{ }} <--False

Thank you - Sep 18th 2009, 11:42 PMGrandad
- Sep 19th 2009, 08:40 AMawkward
Just a comment on g. and Grandad's answer--

The answer depends on your interpretation of the symbol . Some authors define this symbol to mean either proper inclusion or equality of sets. I.e., means every element of A is also an element of B. If your book or teacher defines it this way then your answer is wrong.

Other authors define to mean proper inclusion, i.e. means every element of A is also an element of B but , and write or if A may be a proper subset of B or equal to B. So it depends. - Sep 19th 2009, 10:04 AMzpwnchen
- Sep 19th 2009, 10:13 AMPlato
- Sep 19th 2009, 10:45 AMzpwnchen
- Sep 19th 2009, 10:52 AMPlato
- Sep 19th 2009, 10:54 AMzpwnchen
Thank you!

how about in this case:

A = {0,1,2,3,4,5,6,7,8,9}

B = {0,2,4,6,8}

can we say that A B and A B? But A B, right? - Sep 19th 2009, 11:16 AMPlato
- Sep 19th 2009, 11:22 AMzpwnchen
ops! i'm so sorry that i wrote it wrong.

should be

Quote:

can we say that B A and B A? But A B, right?