My name is on a patent application as first inventor. My friend's name is on a patent application as second inventor.
I'm planning to file a divisional patent application. Does his name have to be included in the divisional patent application?
The true inventors who made conceptual contributions to the subject of any claim being pursued must be listed. If you both made conceptual contributions to claims that appear in the divisional you both are inventors in that application. If the the election you made in the first application in response to the restriction requirement left only claims that a single one of you contributed to then only that person should be on the original. The same thing goes for the divisional. Maybe it is your name that should be left off the divisional.
Also, to patent law, the order of the inventors names is meaningless. Either someone is an inventor or they are not. The rights they get are not apportioned by the amount of their contribution.