Let $\mathfrak{X}$ be a strongly nondegenerate strictly polystable formal scheme over $K^{\circ}$ of dimension $n+1$ with associated skeleton $\Delta$. Consider an $n$-dimensional closed face $\bar{\tau}$ of $\Delta$ with interior $\tau$ and the formal open subscheme $\mathfrak{X}^{\prime}$ of $\mathfrak{X}$ consisting of all formal open subsets $\mathfrak{U}$ with $S(\mathfrak{U})=\bar{\tau}$. Let $h$ be a piecewise affine linear convex function (see Definition 2.10) on $\bar{\tau}$ and $\mathfrak{D}$ a subdivision of $\bar{\tau}$ such that $h\Big|_{\Delta^{\prime}}$ is affine linear for all $\Delta^{\prime}\in\mathfrak{D}$. Let $\iota:\mathfrak{X}^{\prime\prime}\rightarrow\mathfrak{X}^{\prime}$ be the corresponding formal scheme (cf. Construction 2.6). We have seen in Proposition 2.11 that $h$ induces a Cartier divisor $D$ on $\mathfrak{X}^{\prime\prime}$. We set $\mathcal{O}(h\circ p_{\mathfrak{X}^{\prime}}):=\mathcal{O}(D)$ where $p_{\mathfrak{X}^{\prime}}:\mathfrak{X}^{\prime an}\rightarrow\overline{\tau}$ is the restriction of the contraction $p_{\mathfrak{X}}:\mathfrak{X}^{\textup{an}}\rightarrow\Delta$. For a line bundle $\mathfrak{L}$ on a formal scheme, we will denote by $c_{1}(\mathfrak{L})$ the first Chern class of the special fibre of $\mathfrak{L}$.