## Revista Matemática Iberoamericana

### Solution to the gradient problem of C.E. Weil

Zoltán Buczolich

#### Abstract

In this paper we give a complete answer to the famous gradient problem of C. E. Weil. On an open set $G\subset \mathbb{R}^{2}$ we construct a differentiable function $f:G\to\mathbb{R}$ for which there exists an open set $\Omega_{1}\subset\mathbb{R}^{2}$ such that $\nabla f(\mathbf{p})\in \Omega_{1}$ for a $\mathbf{p}\in G$ but $\nabla f(\mathbf{q})\not\in\Omega_{1}$ for almost every $\mathbf{q}\in G$. This shows that the Denjoy-Clarkson property does not hold in higher dimensions.

#### Article information

Source
Rev. Mat. Iberoamericana Volume 21, Number 3 (2005), 889-910.

Dates
First available in Project Euclid: 11 January 2006

http://projecteuclid.org/euclid.rmi/1136999135

Zentralblatt MATH identifier
05034353

Mathematical Reviews number (MathSciNet)
MR2231014

#### Citation

Buczolich, Zoltán. Solution to the gradient problem of C.E. Weil. Rev. Mat. Iberoamericana 21 (2005), no. 3, 889--910. http://projecteuclid.org/euclid.rmi/1136999135.

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