What ⋉ means
It marks a semidirect product, where one group acts on another.
For H ⋉ N, H is the acting group and N is a normal subgroup: conjugating N by elements of the whole product keeps it inside N. That role distinction is why swapping the factors can change the construction.
Unlike a direct product, the factors do not simply commute: the acting group can change elements of the normal group.
Which factor is normal in H ⋉ N?
In the common convention, N on the right is normal.
Unicode's character names call ⋉ the left-normal-factor form and ⋊ the right-normal-factor form; mathematical formula conventions do not always follow those names. Both conventions appear in mathematical texts as of 2026, so follow the local definition.
Technical group-theory notation whose meaning depends on the definition surrounding the formula.
Do not assume the left factor is normal; in common notation H ⋉ N, N is normal.
What it means when someone sends it to you
3 readingsDon't confuse it with
1Combination ideas
3Questions people ask
1Why does ⋉ look different in my document?
It can. As of 2026, Unicode says its reference glyphs are not prescriptive, so mathematical fonts may draw ⋉ with different shapes and spacing.
How to type ⋉
⋉\22C9Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.
