Is it a bad idea to ask my erstwhile PI to say in a recommendation letter he "forgot" to acknowledge me in a prior work? Three years ago, I was an undergrad majoring in Biochemistry in a major US university, and did significant research work in preparation for my thesis.
I am currently polishing a personal statement for PhD applications. To help illustrate a point, I started looking into the publication list of my erstwhile advisor for ideas, for the first time in a year. It turns out he published an article on Nature last year, that credited several fellow undergrads in my lab as co-authors, but not myself. I was never notified of the publication, nor mentioned in the acknowledgement section. The article relied on a database that I helped to compile, and mentioned one of the conclusions I made in my senior thesis. Clearly, it's too late to ask for any revisions to that paper.
Even if these are not sufficient grounds for including me in the author list, I wonder if I am justified in asking that professor to say in his recommendation letter he &quot;forgot&quot; to add me as a co-author, or include me in the acknowledgement section? I had asked him to prepare a recommendation letter months in advance, but it will be at least another week before he is expected to send any.
As for my personal relationship with the professor - his recommendation for me is probably not the most emphatic, but we have generally been on good terms up to this point. Will simply raising this question damage our relationship, or even his recommendations?
You should ask the professor to describe your contribution to the database and the relationship between the database and the publication.
No matter what the reason is that you are not an author on the publication, there is no benefit to including the reason in your letter of recommendation.  A correction to the author list could benefit you, but only someone familiar with the details of your work could determine if that is appropriate.