Fusion systems realizing certain Todd modules

Abstract

Abstract We study a certain family of simple fusion systems over finite 3-groups, ones that involve Todd modules of the Mathieu groups 2 ⁢ M 12 2M_{12} , M 11 M_{11} , and A 6 = O 2 ⁢ ( M 10 ) A_{6}=O^{2}(M_{10}) over F 3 \mathbb{F}_{3} , and show that they are all isomorphic to the 3-fusion systems of almost simple groups. As one consequence, we give new 3-local characterizations of Conway’s sporadic simple groups.