On the minimal degree of a transitive permutation group with stabilizer a 2-group

The minimal degree of a permutation group G is defined as the minimal number of non-fixed points of a non-trivial element of G. In this paper, we show that if G is a transitive permutation group of degree n having no non-trivial normal 2-subgroups such that the stabilizer of a point is a 2-group, then the minimal degree of G is at least 23n. The proof depends on the classification of finite simple groups.