Abstract
The didactical phenomenon reversible and irreversible desemantisation is a key concept and it has been described in detail in (Hejný, Jirotková, Slezáková, 2015). Theoretical background to study of the phenomenon of desemantisation is the theory describing cognitive processes in mathematics, which is developed in (Hejný 2012; 2014) who refers to is as the Theory of Generic Models (TGM).