Update README.md

examples/helmholtzFlow/freefield/README.md

@@ -6,7 +6,7 @@ Dependency(ies):
 
 ## Problem description
 
-These routines solve a convected Helmholtz propagation problem with a Dirac right-hand-side, in either a circular or square domain. 
+These routines solve a convected Helmholtz propagation problem with a Dirac right-hand-side, either in a circular or square domain. 
 Different ABCs are tested on the output boundary, and are compared to the analytical solution.
 
 ## Installation and usage 
@@ -20,10 +20,10 @@ Simply run
 ```
 with `[PARAM]`:
 * `-geometry [x]` where `[x]` is the domain geometry (0: disk, 1: square)
-* `-k [x]` is the freefield wavenumber, $k>0$
-* `-R [x]` where `[x]` is the disk radius or square size, $R>0$
+* `-k [x]` is the freefield wavenumber, $`k>0`$
+* `-R [x]` where `[x]` is the disk radius or square size, $`R>0`$
 * `-xs [x]` and `-ys [x]` specify the point source location
-* `-M [x]` is the mean flow Mach number, $0<M<1$
+* `-M [x]` is the mean flow Mach number, $`0<M<1`$
 * `-theta [x]` is the mean flow angle orientation, $\theta \in [0, 2\pi]$
 * `-abcName [x]` is the ABC type. The available choices are `ABC-0`, `ABC-2`, `Pade` and `pml`
 * `-padeOrder [x]` and `-angle [x]` specify respectively the number of auxiliary function and branch rotation angle for the `Pade` abc.