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golriz
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Is it true?
" Set of interior points of the closure of A equals the set of interior points of A. "
" Set of interior points of the closure of A equals the set of interior points of A. "
golriz said:Is it true?
" Set of interior points of the closure of A equals the set of interior points of A. "
golriz said:I want to prove this theorem:
" Let U be an open subset of a metric space X,and A be an arbitrary subset of X. Prove that the intersection of U and closure of A is empty if and only if the intersection of U and A be empty. "
I've proved one direction of this theorem:
If the intersection of U and closure of A is empty then the intersection of U and A is empty too.
The closure of A is equal to the union of A and the set of all limit points(accumulation points) of A. Then we can use this definition of the closure of A. then after substitution, we have:
[ intersection of A and U ] U [intersection of U and the set of limit points of A] = empty set
so it says that both the sets [ intersection of A and U ] and [intersection of U and the set of limit points of A] should be empty.
This means that the point is contained within the closure of set A and is not on its boundary.
A point is in the interior of the closure of A if there exists a neighborhood of the point that is entirely contained within the closure of A.
Yes, it is possible for a point to be in the interior of the closure of A even if it is not in A. This is because the closure of A also includes all limit points, which may not necessarily be in A.
Yes, the interior of the closure of A is always a subset of the closure of the interior of A. This is because the interior of A only includes points that are entirely contained within A, while the closure of A includes all limit points as well.
No, a point cannot be in the interior of the closure of A if it is on the boundary of A. This is because the interior of the closure of A only includes points that are not on the boundary of A.