Section ExtraspecialFormspace.
Variable G : {group gT}.
Hypotheses (pG : p.-group G) (esG : extraspecial G).
Let p_pr := extraspecial_prime pG esG.
Let oZ := card_center_extraspecial pG esG.
Let p_gt1 := prime_gt1 p_pr.
Let p_gt0 := prime_gt0 p_pr.

(* This encasulates Aschbacher (23.10)(1). *)
Lemma cent1_extraspecial_maximal x :
x \in G -> x \notin 'Z(G) -> maximal 'C_G[x] G.