1. Assignment problems encountered in LCAs

1.1 Notions and concepts

A system is made up of transformation, transport and storage processes. It can have inputs and outputs of materials (metals, plastics, etc.), energies (solar energy, heat, energy contained in energetic materials, etc.) or spaces (ground surfaces, volumes, etc.) (figure 1 ). These are the three types of resources that can circulate [1] . In a socio-economic representation (figure 2 ), these incoming and outgoing flows can be waste (processed rubbish, used...