If an indiscrete topological space $X$ is metrizable then $X$ is necessarily a singleton whereas it can be any set without metrizability. Proof: Fix $x$. $B(x,r)=X$ for any $r>0$ so $d(y,x)
If an indiscrete topological space $X$ is metrizable then $X$ is necessarily a singleton whereas it can be any set without metrizability. Proof: Fix $x$. $B(x,r)=X$ for any $r>0$ so $d(y,x)