主题：【原创】谈谈时间序列的平稳性（1） -- 万里风中虎

And ITO lemma is applied to random walk. Price is modeled as brownian motion (one kind of random walk). But I think it's more relevant to continuous t.

That's beyond my capacity. Don't know how to explain it in Chinese (don't get me wrong, I'm not proud of it. I don't know the translations of most terminologies.Explaining is not what i'm good at. Questioning is, as you can see). It's more efficient if you can grab an econometrics book in chinese. Random walk is a very basic and popular topic.

Not really. It's a notorious topic generated years of debate. If stock price is random walk, then the market is efficient and all the modelers will lose their job. Now you understand what they are fighting for.