If X determines Y and X determines Z then X must also determines Y and Z.
This is suggesting that if two tables are separate, and the PK is the same, you may want to consider putting them together.
SIN —> EmpName
SIN —> SpouseName
You may want to join these two tables into one.
SIN –> EmpName, SpouseName
Some DBAs would leave them separated for a couple of reasons. They describes two entities, so should be separated. If in one table, the spouse name may be left NULL most of the time, so there is no need to have it in the same table.