Talk:Kantorovich theorem

Euclidean space
Why is everything couched in Euclidean space? Is there not a version that applies to any Banach spaces? 203.167.251.186 (talk) 01:22, 15 July 2010 (UTC)


 * Actually, it is the same. One would have to add technicalities like that source and target space could be different Banach spaces, however the derivative in x0 has to define an homeomorphism of both spaces, one could discuss the choice of different equivalent norms etc. The german version has a paragraph to that effect.--LutzL (talk) 08:29, 15 July 2010 (UTC)

Locally Lipschitz
I think the definition given of locally Lipschitz is wrong. Take the open set to equal to the whole space. Really given any point there should exist an open set, is that correct? — Preceding unsigned comment added by 2607:EA00:107:3C01:6045:2882:4736:C33 (talk) 17:50, 20 November 2015 (UTC)

Definition currently given is:

Let $$X\subset\R^n$$ be an open subset and $$F:\R^n\supset X\to\R^n$$ a differentiable function with a Jacobian $$F^{\prime}(x)$$ that is locally Lipschitz continuous (for instance if it is twice differentiable). That is, it is assumed that for any open subset $$U\subset X$$ there exists a constant $$L>0$$ such that for any $$\mathbf x,\mathbf y\in U$$


 * $$\|F'(\mathbf x)-F'(\mathbf y)\|\le L\;\|\mathbf x-\mathbf y\|$$

holds. — Preceding unsigned comment added by 2607:EA00:107:3C01:6045:2882:4736:C33 (talk) 17:52, 20 November 2015 (UTC)

Assessment comment
Substituted at 02:16, 5 May 2016 (UTC)