No. Any nonempty subset $A ≠ X$ is open, as well as its complement. So $X$ is the union of disjoint nonempty open subsets.
Is there a more formal way of doing it? Thanks for your help.
No. Any nonempty subset $A ≠ X$ is open, as well as its complement. So $X$ is the union of disjoint nonempty open subsets.
Is there a more formal way of doing it? Thanks for your help.