والخلع والطلاق، وتزوج الزوج بأختها وأربع سواها
Khulʿ, a further divorce, marriage to a former wife's sister, and some cases involving marriage to four other women can be connected to whether a marriage or waiting period continues.
The purpose is not to pronounce a ruling on every individual case. It is to see how many subsidiary rulings can follow from disagreement about the meaning of a single legal expression.
Where a prohibition depends on the continued existence of a legal status, the time at which that status ends must be determined before assessing a proposed exception or permission. The fixed number remains three even when other interpretive issues produce differing outcomes.