The symbolic computation of integrability structures for partial differential equations: Errata

Below is a list of known misprints in the book The symbolic computation of integrability structures for partial differential equations.

1. Page 57, the only displayed formula should be

   $L=(\frac{1}{3}u(u_{xx}{u}_{tt}-u_{xt}^2)-\frac{1}{2}(u_x{u}_z+u_t{u}_y))dx\wedge dz\wedge dt\wedge dy.$

   (change the minus sign before $u_t{u}_y$ into plus).

2. Page 195, equation (10.9), replace it with

   $\sum _j\frac{\delta {\mathrm{\Phi }}_{{𝒫}}}{\delta p^j}{p}^j=-2{\mathrm{\Phi }}_{{𝒫}}$

   (multiply the left-hand side by $p^j$ to the right).