(1) A INTERSECTION {A}
A may have many elements, but none of which is A itself.
A set is NEVER an element of itself.
However,
{A} has just one element, A.
Therefore A and {A} have NO ELEMENTS in common! Therefore
their intersection is empty.
Answer: the empty set.
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{A,{A}}-A
We remove A from the set and that leaves {{A}},
it must have two braces on each side of A.
That is the set that contains as its only element
the set that contains A as its only element.
Answer {{A}}
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Edwin
