A relative time reference in @if statements.
The opening period is the aggregate of the closing and deal periods.
True—if the period is subperiod with zero days
If 2007 is in years and 2008 is comprised of two subperiods, one of 365 days and another of zero days, this formula:
@if(@issub, 1, 2)
If this function was built using Using User-Defined Accounts, the 2008 aggregate period returns a 2.