I'm not necessarily sure how to approach this problem—or whether it even has a solution—but I would like to know an example of a non-constant function that satisfies this condition:
Also, could someone point me to a good book that can help me with these types of questions?
*edit: By the way, I really don't care how this function would look like—if it ends up being a matrix, that'll do.
Thank you all!
**Edit: I probably should clarify that the 1 means identity. I'm putting that info down because I'm not sure what the answer could be, but I would like it to refer as an identity.