A few more distinctions when considering causation include necessary and sufficient.
What is a necessary cause?
Basically, this means that w must be present for v to occur. If w is a necessary cause of v, then the presence of w necessarily implies the presence of v; however, the reverse is not true by default. A phenomenon of v, however, does not imply that w occurs.
Example: Oxygen must be present for fire; however, the fact a room contains oxygen does not automatically imply that there is also a fire in the room.
What is a sufficient cause?
If x is a sufficient cause of y, then the presence of x necessarily implies the presence of y. However, another cause z may alternatively cause y. Thus the presence of y does not imply the presence of x.
Example: An election results in someone being elected President of a country; however, the fact a country has a President does not imply elections. In fact, a President might acheive power through a military coup.