Dates
Fast calendar calculations for 10,000 years (Julian and Gregorian)
...Not only that they will expire sooner or later due to number overflow. Not only that this will make calendarian calculations extremely complicated. Fact is, that this will combine two things together which don't have anything to do with each other: The rotation of the earth around itself and the rotation of the earth around the sun, which in addition will both vary during the chiliads. So how will you be able to do date calculations if you then even try to consider time gimmicks like summer/winter time changes, leap-seconds and so on? Just forget it!
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