Inspired by the following question: Co-authorship for not very involved supervisor
I have got to ask a slightly different question: I have a past supervisor while I did my masters and she wasn't really involved or as active as I would have liked. Also, I received no funding from this professor. I did however receive a scholarship from the university to fund my masters; not sure if these facts change anything. Naturally, this person would also like to believe she was involved, so had I finished the research while I did my masters there I would have listed this individual as a second author and even the author of correspondence. But now I am pursuing a PhD and in fact in a slightly different field at a different university.
While preparing for my qualifiers I came across some fresh new ideas and had a light bulb moment. Consequently, I have made significant progress in my old project as of late. I believe by the end of the summer I will have results ready for publication. On the one hand, I feel I should notify my old professor of these results once they come in... I think it would be wrong or even unethical to let them find out through the grape-vine or just through reading to keep up with the field. On the other hand, I fear this person will want authorship or even write the editor and demand it; this person is a Reader at a prestigious university while I'm just a little PhD student. I feel it will be a case of he-said she-said with the Editor which will ultimately result in me losing (even though I completely believe I'm justified and the recent progress was 100% mine).
Maybe I'm over-reacting but I'm not sure what to do. And I certainly don't want this person to "read over" my paper or attempt to "edit" it, because I think then they would have more grounds to put their name on the paper. Any ideas?