[Doc] Fix latex expression for beta.

web/content/docs/benchmarks/hydro-component/hydro-component.md

@@ -23,7 +23,7 @@ The development of the equation system is given in [this PDF](../HC-Process.pdf)
 
 ## Problem description
 
-We use quadratic mesh with $0 < x < 1$ and $0 < y < 1$ and a resolution of 32 x 32 quad elements with edge length $0.03125 m$. The domain material is homogeneous and anisotropic. Porosity is $0.2$, storativity is $10^{-5}$, intrinic permeability is $1.239 \cdot 10^{-7} m^2$, dynamic viscosity is $10^{-3} Pa \cdot s$, fluid density is $1 kg\cdot m^{-3}$, molecular diffusion is $10^{-5} m^2\cdot s^{-1}$. If not stated otherwise, retardation coefficient is set to $R=1$, relation between concentration and density is $beta_c = 0$, decay rate is $\theta = 0$, and dispersivity is $\alpha = 0$.
+We use quadratic mesh with $0 < x < 1$ and $0 < y < 1$ and a resolution of 32 x 32 quad elements with edge length $0.03125 m$. The domain material is homogeneous and anisotropic. Porosity is $0.2$, storativity is $10^{-5}$, intrinic permeability is $1.239 \cdot 10^{-7} m^2$, dynamic viscosity is $10^{-3} Pa \cdot s$, fluid density is $1 kg\cdot m^{-3}$, molecular diffusion is $10^{-5} m^2\cdot s^{-1}$. If not stated otherwise, retardation coefficient is set to $R=1$, relation between concentration and density is $\beta_c = 0$, decay rate is $\theta = 0$, and dispersivity is $\alpha = 0$.
 
 Boundary conditions vary on the left side individually for each setup; right side is set as constant Dirichlet concentration $c=0$; top and bottom are no-flow for flow and component transport. Initial conditions are steady state for flow (for the equivalent boundary conditions respectively) and $c=0$.
 
@@ -58,7 +58,7 @@ Left side boundary conditions for these setups are pressure $p=1$ and concentrat
 
 #### Diffusion, Storage, Gravity, and Dispersion
 
-Boundary condition for this setup is pressure $p=0$ for the top left corner and concentration $c=1$ for half of the left side. Relation between concentration and gravity is $beta_c = 1$.
+Boundary condition for this setup is pressure $p=0$ for the top left corner and concentration $c=1$ for half of the left side. Relation between concentration and gravity is $\beta_c = 1$.
 
 [The *Diffusion, Storage, Gravity, and Dispersion* project file is here. ](../../../../../Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndGravityAndDispersionHalf.prj)