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## sasogeek Group Title a null set and an empty set, are they the same? 2 years ago 2 years ago

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1. mathteacher1729

Hi @sasogeek , in every context I've ever seen, null set and empty set mean the same thing. A set with no elements.

2. sasogeek

well we had an exam and the teacher asked which of the following options was a null set. a. b.{} c.{0} d.$$\phi$$

3. mathteacher1729

Heh. If I were grading this, I'd accept b or d. Perhaps your professor has a preferred notation? Here is the definition from Wolfram Mathworld: http://mathworld.wolfram.com/NullSet.html

4. sasogeek

i chose d though

5. sasogeek

so i guess i'm wrong...? since $$\phi$$ denotes {} ?

6. mathteacher1729

To me, this is splitting hairs. I'd ask your professor if s/he has a preferred notation and go with that for future reference.

7. sasogeek

i asked him during the test and he said it was meant to confuse us but he'll tell us the answer next class so i look forward to questioning him tomorrow since tomorrow is the next lecture :)

8. mathteacher1729

Strange. Well, to each their own. For me, I try to make definitions and notation as clear as possible from day 1. ;-p But that's me.

9. sasogeek

hmmm oh well. i guess i'd never know which answer he's in search of unless he utters it himself. thanks for the help though :) that link helped a bit. and i appreciate your input x