>because the algorithms they're talking about depend on the Lipschitz property, not the differentiability. That is why the definition should not contain the di

>because the algorithms they're talking about depend on the Lipschitz property, not the differentiability. That is why the definition should not contain the differentiability condition. It is violated by the examples and irrelevant. My point is that the Lipschitz property, as defined e.g. in the Wikipedia article, is the important part. Also assuming differentiability is unhelpful, because it misses the point and is even violated by the rest of the article.