In short, a litepaper is usually shorter and not as detailed as a whitepaper. Usually, the technical part is kept very short. It is like a teaser of a whitepaper. A whitepaper is more comprehensive and describes the fundamental and technical details of the crypto project. A yellow paper focuses on the technical and mathematical part of the crypto project. It contains a lot of complex equations, scientific analysis, and proofs which are not covered in extensive depth in a whitepaper.