The PHP ternary operator is a shorthand way of writing an if/else statement.

The logic of the Ternary Operator is

// basic ternary logic
$result = (condition) ? return if true : return if false ;

A working example would be something like

// working example of ternary operator

$due = 9;
$timenow = 10

$late = ($due < $timenow) ? true : false ;

Written in long hand

// working example of ternary operator

$due = 9;
$timenow = 10

if ($due < $timenow) :
    $late = true;
else:
    $late = false;
endif;

For more info on php comparison operators and in particular the ternary operator see the php manual

http://us2.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary