The usual symbol for normal subgroup is a triangle with a line under it
How do you get this symbol in Latex - ie how do you write
H is a normal subgroup of G in the usual symbols
Peter
[TEX]H\unlhd G[/TEX] gives $\displaystyle H\unlhd G$. (That works with the compiler that this forum uses. In other environments, you may have to call the latexsym package.)