Update README.md

README.md

@@ -14,7 +14,7 @@ C(t,\tau)v(t,t_0,\tau)  = \lambda(t,t_0, \tau) C(t_0, \tau)v(t,t_0,\tau)
 The two time parameters \tau and t_0 can be choosen by the user before compiling the code in the setting options.
 The  effective energy spectrum is determined from:
 ```math
-E_n^{eff}(t, t_0, \tau) = \log( frac{\lambda_n(t, t_0, \tau)}{\lambda_n(t+a, t_0, \tau)}) = E_n + O(e^{-(E_m-e_n)t})  
+E_n^{eff}(t, t_0, \tau) = \log( \frac{\lambda_n(t, t_0, \tau)}{\lambda_n(t+a, t_0, \tau)}) = E_n + O(e^{-(E_m-e_n)t})  
 ```
 Finally the energy levels are determined by fitting the effective energy with the functional form 
 ```math