`PiecewiseExpand`¶

Expands functions to explicit Piecewise form.

$ wo 'PiecewiseExpand[Max[x, y]]'
Piecewise[{{x, x - y >= 0}}, y]

A Piecewise nested inside another collapses into a single one, with the merged conditions reduced:

$ wo 'PiecewiseExpand[Piecewise[{{Piecewise[{{1, x < 1}}, 2], x > 0}}, 3]]'
Piecewise[{{1, Inequality[0, Less, x, Less, 1]}, {2, x >= 1}}, 3]

Abs and Sign split only once a second argument puts them over the reals:

$ wo 'PiecewiseExpand[Abs[x], Reals]'
Piecewise[{{-x, x < 0}}, x]

An assumption that decides the branch collapses the result:

$ wo 'PiecewiseExpand[Abs[x], x > 0]'
x

PiecewiseExpand¶