x1 (event/date) is before x2 (event/date) by x3 (li; integer) days; x1 is x3 days before x2.
Typically will assume linear time. However, recurring events/holidays/named dates will behave cyclically unless the cycle label (such as Gregorian year label for annual holidays) is used; in these contexts, x3 will be multivalued (in terms of acceptable submissions) and could even be negative; for example, a generic Christmas is always x3 = 7 days ahead of the nearest New Year's Day in the Gregorian calendar. See also: "prulamdei", ".utka'au".