Exercises
[0MX]We generalize the definition of metric space assuming that \(d:X→[0,∞]\) (the other axioms are the same). Show that the relation \(x∼ y\) defined by
\[ x∼ y\iff d(x,y){\lt}∞ \]is an equivalence relation, and that equivalence classes are open, and therefore are disconnected from each other.
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