typo

Existing Wording:

Note that as with the before and after transformations, a null test is required here because if B is null, then the constructed interval would be incorrectly interpreted as continuing to the beggining or end of time (depending on whether the null appears as the starting or ending boundary of the interval)\.

Proposed Wording:

Note that as with the before and after transformations, a null test is required here because if B is null, then the constructed interval would be incorrectly interpreted as continuing to the beginning or end of time (depending on whether the null appears as the starting or ending boundary of the interval)\.