It seems all of these four words can denote 'at the same time' or 'if and only if', but do the meanings of them identical?
Update: e.g.
Day comes where the sun rises.
Day comes whereas the sun rises.
Day comes while the sun rises.
Day comes whenever the sun rises.
Update: e.g.
An integer is even where it is divisible by 2.
An integer is even whereas it is divisible by 2.
An integer is even while it is divisible by 2.
An integer is even whenever it is divisible by 2.
