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usual topology and metric toplology [closed]

can you give me an counter examples to metric topology is a usual topology but a usual topology need not be a metric topology?

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 "Usual topology" would depend on the context, but commonly refers to the topology on $\mathbb{R}^n$ induced by the Euclidean metric, in which case there would be no such counter-examples. – Mark Grant Jan 13 2012 at 12:29 @diriba: This question is more appropriate for math.stackexchange, where I encourage you to ask it. – Jim Conant Jan 13 2012 at 12:37 I would encourage the OP to think about it, instead of pestering people. – Igor Rivin Jan 13 2012 at 12:43 @diriba: A better way of phrasing your question is this: show me an example of a topology that is not metrizable. – Mahdi Majidi-Zolbanin Jan 13 2012 at 17:29