Percolation theory and complementary currencies

Complementary currencies experienced for the last three decades a remarkable develop- ment. Originally created in situations of economical crisis they are also used today to promote local, social or commercial purposes. New complementary currency systems are frequently started all over the world, with or without the expected success. For exam- ple, in the small Belgian municipality of Ottignies-Louvain-la-Neuve, a complementary currency was first launched in 2014 without much success and relaunched only recently in 2017. On another note, network theory is increasingly used today to model and study economic networks. Markets are modelled as networks of bilateral exchanges in order to understand better their functioning. However, the literature covering applications of network theory tools to complementary currency systems is limited. There is to our point of view a lack of network theory approach in the complementary literature. This master thesis first extracts from the complementary currency literature the contributions with a network theory approach. It then uses percolation theory to build a viability threshold for complementary currency systems. A key element consists in the need of circularity, for a complementary currency system to prosper.