Strong link

A strong link exists between 2 candidates when one of them must be true. Strong links can be present in bivalue cells, in bilocal units and in Almost Locked Sets.

For candidates A and B which have a strong link, we can make the following logical deductions:

• If A is false, B must be true.
• If B is false, A must be true.

For bivalue cells and bilocal units, a strong link also enforces a weak link.