In finite group theory, an area of abstract algebra, a strongly embedded subgroup of a finite group G is a proper subgroup H of even order such that H ∩ Hg has odd order whenever g is not in H. The Bender–Suzuki theorem, proved by Bender (1971) extending work of Suzuki (1962, 1964), classifies the groups G with a strongly embedded subgroup H. It states that either Peterfalvi (2000, part II) revised Suzuki's part of the proof.
Aschbacher (1974) extended Bender's classification to groups with a proper 2-generated core.