 The special case of a geometric L\'evy model (GLM) with constant parameters can be regarded as a natural generalisation of the standard geometric Brownian motion model  used in the  Black-Scholes theory .
<clarity>  The special case of a geometric L\'evy model (GLM) with constant parameters can be regarded as a natural generalisation of the standard geometric Brownian motion model  used in the  Black-Scholes theory .
 The special case of a geometric L\'evy model (GLM) with constant parameters can be regarded as a natural generalisation of the standard geometric Brownian motion model (GBM) used in the Black-Scholes theory .