Conjectures on Character Degrees for the Simple Lyons Group

We prove a version of the Isaacs–Navarro conjecture for the simple Lyons group. The original conjecture is a refinement of the Alperin–McKay conjecture which deals with irreducible characters of height zero and the normalizer of a defect group. But we look also at the normalizers of radical p‐chains and consider the alternating sum of the numbers of characters of any given defect.