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1 votes
1 votes
Write the set

$\left \{ \phi ,\left \{ \phi \right \} \right \}-\phi$
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2 Answers

Best answer
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3 votes

Here $\phi$ to be subtracted is an empty set.

Hence, $\left \{ \phi,\left \{ \phi \right \}\right \}$ -  $\phi$ = $\left \{ \phi,\left \{ \phi \right \}\right \}$

Had it been $\left \{ \phi, \left \{ \phi \right \}\right \} - \left \{ \phi \right \}$ , we would have gotten $\left \{ \left \{ \phi \right \}\right \}$

Consider like A = {2,3,4} and B = {2}

A - $\phi$ = A

But A - 2 makes no sense. Rather A - {2} does!

edited by
1 votes
1 votes
Something - Nothing = Something

 

{ϕ,{ϕ}}−ϕ = {ϕ,{ϕ}}

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