*Preprint*

**Inserted:** 12 oct 2017

**Last Updated:** 12 oct 2017

**Year:** 2017

**Abstract:**

We introduce a notion of Lagrangian representation for entropy solutions to scalar conservation laws in several space dimensions \[ \begin{cases} \partial_t u + \text{div}_x (\mathbf{f}(u)) = 0 & (t, x) \in (0, +\infty) \times \mathbb R^d,\\ u(0, \cdot) = u_0(\cdot) & t = 0. \end{cases} \] The construction is based on the transport collapse method introduced by Brenier. As a first application we show that if the solution $u$ is continuous, then its hypograph is given by the set \[ \{ (t, x, h) : h \le u_0 (x - f (h)t) \}, \] i.e. it is the translation of each level set of $u_0$ by its characteristic speed.

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