The Mathematics of Daylight Saving Time End

In many places, clocks fall back on the first Sunday of November. This is a piecewise linear transformation of time: t' = t – 1 hour for 2 AM onward, with a repeat of the 1 AM‑2 AM hour. The mathematics of time zones (mod 24) and the history of DST (first proposed by George Hudson, 1895) involve optimisation of daylight utilisation. The shift disrupts sleep patterns, and the effect can be modelled by a cosine function (circadian rhythm). DST is an applied optimisation problem: do the benefits outweigh the costs?