“…In the last two or three decades however, the range of available mathematical models has been considerably enlarged as a result of the development of new modelling paradigms such as Fuzzy Set theory [29,31,60,84,85] and also due to the needs for new problem-solving techniques on graphs [1,48,74,75,78,79,86,87] and new Operations Research applications [3,8,17,37,80,88]. From these recent evolutions, the basic algebraic structures referred to as dioïds and semirings have emerged, somewhat systematically (often under different names), in modelling and solving an extremely rich variety of problems.…”