3-NIRVANA-user-guide/3.2-User-interfaces.md

@@ -258,9 +258,9 @@ possible values or a numeric range.
         conditions. The type of boundary condition at a physical domain
         boundary is characterized by a single capital letter. It are
         grouped in a 6-letters word with the individual letter
-        representing, from left to right, the lower-$x$ (`_C.bc[0]`),
-        upper-$x$ (`_C.bc[1]`), lower-$y$ (`_C.bc[2]`), upper-$y$
-        (`_C.bc[3]`), lower-$z$ (`_C.bc[4]`) and upper-$z$ (`_C.bc[5]`)
+        representing, from left to right, the lower-**x** (`_C.bc[0]`),
+        upper-**x** (`_C.bc[1]`), lower-**y** (`_C.bc[2]`), upper-**y**
+        (`_C.bc[3]`), lower-**z** (`_C.bc[4]`) and upper-**z** (`_C.bc[5]`)
         domain boundary. Possible boundary condition types are
         ($u_{i/o}$: inner/outer-domain boundary values of a variable
         $u$):
@@ -297,14 +297,14 @@ possible values or a numeric range.
             $u_o=u_i$ for the perpendicular magnetic field component.
 
         -   `R`: reflection-on-axis (only of relevance in cylindrical
-            geometry at the $y$-lower boundary at $R=0$ or in
-            spherical geometry at the $y$-lower/upper boundaries at
+            geometry at the **y**-lower boundary at $R=0$ or in
+            spherical geometry at the **y**-lower/upper boundaries at
             $\theta =0,\pi$) - reflecting conditions at the geometric
             axis. Same as M except for the azimutal magnetic field
             component for which $u_o=-u_i$.
 
         -   `C`: reflection-at-center (only of relevance in spherical
-            geometry at the $x$-lower boundary at $r=0$) - reflecting
+            geometry at the **x**-lower boundary at $r=0$) - reflecting
             conditions at the coordinate center. Same as M except for
             the non-radial magnetic field components for which
             $u_o=-u_i$.
@@ -316,9 +316,9 @@ possible values or a numeric range.
             (pseudo-vacuum condition) for the magnetic field.
 
         -   `F`: free boundary (only of relevance in cylindrical
-            geometry at the $y$-lower boundary at $R=0$ or in
-            spherical geometry at the $y$-lower/upper boundaries at
-            $\theta =0,\pi$ and $x$-lower boundary at $r=0$) -
+            geometry at the **y**-lower boundary at $R=0$ or in
+            spherical geometry at the **y**-lower/upper boundaries at
+            $\theta =0,\pi$ and **x**-lower boundary at $r=0$) -
             'natural' boundary condition at the geometric axis. Boundary
             values are not set explictely but are implicitly given by
             $\pi$-shifted values. Note that when a `F`-type boundary