# Subgroup property timeline

## Pre-World-War II

- 1829-33: Galois introduced the notions of subgroup and normal subgroup (in a very loose fashion) in his monumental work linking groups to Galois extensions
- 1895: Frobenius introduced the notion of characteristic subgroup
- 1933: Levi introduced the notion of fully characteristic subgroup
- 1937: Oystein Ore introduced the concept of quasinormal subgroup, which is now known as permutable subgroup

## 1945-1990

- 1961: Carter introduced the notions of abnormal subgroup and Carter subgroup in his paper
*Nilpotent self-normalizing subgroups of soluble groups*,*Math. Zeitschr. 75, 136-139 (1961)* - 1967: John S. Rose introduced the notion of pronormal subgroup in his paper
*Finite soluble groups with pronormal system normalizers*

## 1990 onwards

- 1996: Wang introduced the notion of c-normal subgroup
- 1996: Foguel introduced the notion of conjugate-permutable subgroup
- 2001: Wise introduced the notion of cyclonormal subgroup
- 2002: Zhum Guo and Shum introduced the notion of weakly c-normal subgroup