Before revision:  The proposed model is symmetric with respect to the choice of the risk-free currency , opening up to new approaches for coherent pricing and risk management of derivatives depending on multiple currencies .
After revision:  The proposed model preserves the natural inversion and triangulation symmetries of FX spot rates and its functional form, irrespective of choice of the risk-free currency , opening up to new approaches for coherent pricing and risk management of derivatives depending on multiple currencies .