| 1 | This first implementation follows the guidelines [https://groups.google.com/d/msg/sage-support/wLo2RQ-KSag/uyimvFsoCAAJ suggested] by Ralf Stephan. It is probably highly perfectible : |

| 2 | * The implementation is "pure Sage" : I am aware of the possibility of speeding it considerably by declaring types to the necessary functions and their arguments, but I'm unsure about the relevant types (I'm quite novice in Cython...). |

| 3 | * I am not sure that this distribution should occur in every expansion : one could add a keyword to the {{{expand()}}} method/function, with edault value being either True or False (to be discussed). |

| 4 | * Since the {{{expand()}}} method essentially dispatches the work to the components of the {{{Expression}}}, This specialized expansion could (should ?) take place as a method of {{{Function_sum}}}, but I'm currently unablke on how to do this (this is my first ever attempt to work on the Sage symbolics in the library). |

| 5 | |

| 6 | Suggestions, criticisms, even lazzi are welcome as long as they are constructive... |

| 7 | |

| 8 | I'm not marking this as {{{needs_review}}}, since the documentation remains to be written. I may push a documentation patch and mark it {{{needs_review}}} soon. |