diff --git a/src/2_debye_model.md b/src/2_debye_model.md
index c6c7e4aa8c4108a8fc6bb4837864af33dbd8383d..41e2f155e1756eee8d7fcd1765351b13118958fd 100644
--- a/src/2_debye_model.md
+++ b/src/2_debye_model.md
@@ -276,10 +276,10 @@ ax.legend(loc='lower right');
 ## Conclusions
 
 1. The Debye model assumes that atoms in materials move in a collective fashion, described by normal modes / sound waves with a dispersion relation $ω = v_{\rm s}|\mathbf{k}|$.
-2. The normal modes have a constant density of $(L/2Ï€)^3$ in the reciprocal space.
+2. The normal modes have a constant density of $(L/2Ï€)^3$ in $k$-space.
 3. The total energy and heat capacity are given by integrating the contribution of the individual modes over $k$-space.
 4. The density of states $g(ω)$ counts the number of modes per unit frequency. $g(ω)$ is proportional to $ω^2$ for 3D bosons with a dispersion relation $ω = v_{\rm s}|\mathbf{k}|$.
-5. At low temperatures the phonon heat capacity is $∼T^3$.
+5. At low temperatures the phonon heat capacity is $\propto T^3$.
 
 
 ## Exercises