Practice problem
What choices below represent semidirect products of N,HN,HN,H in which NNN must be a normal subgroup?
N⋉HN\ltimes HN⋉H
H⋉NH\ltimes NH⋉N
N⋊HN\rtimes HN⋊H
H⋊NH\rtimes NH⋊N
N◃HN\triangleleft HN◃H
H◃NH\triangleleft NH◃N
N×HN\times HN×H
H×NH\times NH×N
Type a concept, like “slope” or “photosynthesis”.