TITLE: When should a supervisor be a co-author?
QUESTION [157 upvotes]: What are people's views on this?  To be specific: suppose a PhD student has produced a piece of original mathematical research. Suppose that student's supervisor suggested the problem, and gave a few helpful comments, but otherwise did not contribute to the work.  Should that supervisor still be named as a co-author, or would an acknowledgment suffice?
I am interested in two aspects of this. Firstly the moral/etiquette aspect: do you consider it bad form for a student not to name their supervisor?  Or does it depend on that supervisor's input?  And secondly, the practical, career-advancing aspect: which is better, for a student to have a well-known name on his or her paper (and hence more chance of it being noticed/published), or to have a sole-authored piece of work under their belt to hopefully increase their chances of being offered a good post-doc position?
[To clarify: original question asked by MrB ]

REPLY [2 votes]: I believe it to be in bad taste for advisors to co-author a paper with their current student, no matter what their relative contributions. Of course, I am in pure mathematics, and understand that they do things differently in other parts of mathematics, and in other disciplines. Otherwise, there is the possibility of an advisor exploiting their position. This strict policy also obviates any soul-searching about how much contribution is required to be a co-author.
Of course, it is expected that the student will acknowledge in the paper, the help  (if any) received from their advisor.