(a)
Notwithstanding section 6101 of this title, each agency may establish programs which use a 4-day workweek or other compressed schedule.
(b)
(1)
An employee in a unit with respect to which an organization of Government employees has not been accorded exclusive recognition shall not be required to participate in any program under subsection (a) unless a majority of the employees in such unit who, but for this paragraph, would be included in such program have voted to be so included.