Specifically, I'd be very grateful if you may refer me to any literature treating wealth or income inequality or both, but the important thing is that it studies the relationship from a theoretical point of view, i.e. that it develops a mathematical model, preferably microfounded but it is not a requisite. Also, please refer only to "mainstream" literature (hopefully that term makes sense).
By "literature" I mean mostly papers or textbooks.
Please tell me if you need me to be more specific. I read this question, but it is more broad since it is asking for an answer to the topic not about the literature that tries to answer it, also seems like it does not have quality answers.