Figure 5: (a) The system evolves, according to Definitions 1 and 2, from an initial state (top) to other states by a sequence of transformations 𝑆 (arrows) that are directional, that is, dissipative due to the distinct domains 𝐷 and ranges 𝑃 for distinct elements λ of process generators. (b) The successive transformations 𝑆 𝜆 and 𝑆 𝜆 can be reduced to 𝑆 𝜆 𝜆 only when the intermediate state cannot be transformed by any other process 𝜆 .