{* *! version 1.0.2  19apr2007}{...}
{p 4 6 2}
where {it:a} and {it:b} may be numbers or variables;
{it:a} missing ({it:a} {ul:>} {cmd:.}) means minus infinity, and
{it:b} missing ({it:b} {ul:>} {cmd:.}) means plus infinity; see {help missing}.
{p_end}
