>>>>> "Pietro" == Pietro Pugni <pietro(dot)pugni(at)gmail(dot)com> writes:
Pietro> The whole point (for leap years) is:
Pietro> - inconsistency (adding and subtracting the same quantity to a
Pietro> date should provide the date itself, but it doesn't);
It should be obvious that this is mathematically impossible; a function
from a larger set (the 366 days of a leap year) to a smaller one (the
365 days of a common year) cannot have an inverse.
--
Andrew (irc:RhodiumToad)