Finish trailing sentence (#270)

Author: jorgensd

chapter2/amr.ipynb

@@ -324,7 +324,8 @@
     "+ \\sum_{E\\in\\mathcal{F}_i}\\frac{h}{2} \\vert [\\nabla \\cdot \\mathbf{n}_E ]\\vert^2~\\mathrm{d}s\n",
     "\\end{align*}\n",
     "\n",
-    "where $\\mathcal{T}_h$ is the collection of cells in the mesh, $\\mathcal{F}_i$ the collection"
+    "where $\\mathcal{T}_h$ is the collection of cells in the mesh, $\\mathcal{F}_i$ the collection of interior facets\n",
+    "(those connected to two cells)."
    ]
   },
   {

chapter2/amr.py

@@ -199,7 +199,8 @@ def solve(
 # + \sum_{E\in\mathcal{F}_i}\frac{h}{2} \vert [\nabla \cdot \mathbf{n}_E ]\vert^2~\mathrm{d}s
 # \end{align*}
 #
-# where $\mathcal{T}_h$ is the collection of cells in the mesh, $\mathcal{F}_i$ the collection
+# where $\mathcal{T}_h$ is the collection of cells in the mesh, $\mathcal{F}_i$ the collection of interior facets
+# (those connected to two cells).
 
 
 def mark_cells(uh_r: dolfinx.fem.Function, lam: float):