[FRIAM] Manifold Enthusiasts

[Frank Wimberly]

Perhaps annoying clarification.  The word closure has two important
meanings.

In a topological space a set is closed if it is the complement of an open
set.

In the more concrete case of Rn, which we're talking about, a set is closed
if it contains it's limit points (boundary).

The other use of closure is the one Glen(?) mentioned.  The sum of two
elements in the set is in the set and the same for other operations.

Barry, help!

Frank

-----------------------------------
Frank Wimberly

My memoir:
https://www.amazon.com/author/frankwimberly

My scientific publications:
https://www.researchgate.net/profile/Frank_Wimberly2

Phone (505) 670-9918
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