# symbol for proper ideal (\unlhd + \lneq)

How can I write the symbol

for a proper ideal?

The standard relations \leq,\subseteq both have a "proper" version \lneq,\subsetneq, but I was unable to find a "proper" version of either \unlhd or \trianglelefteq.

Any suggestions?

You can do by superimposing the symbols:

\documentclass[a4paper]{article}
\usepackage{amssymb}

\newcommand{\properideal}{%
\mathrel{\ooalign{$\lneq$\cr\raise.22ex\hbox{$\lhd$}\cr}}}

\begin{document}
$I\properideal A$
\end{document}


A version that changes size in subscripts/superscripts; some artifacts may appear at low screen resolution.

\documentclass[a4paper]{article}
\usepackage{amsmath}
\usepackage{amssymb}

\makeatletter
\DeclareRobustCommand{\properideal}{\mathrel{\text{$\m@th\proper@ideal$}}}
\newcommand{\proper@ideal}{%
\ooalign{$\lneq$\cr\raise.22ex\hbox{$\lhd$}\cr}%
}
\makeatother
\begin{document}
$I\properideal A_{\properideal_{\properideal}}$
\end{document}


• Is there any other way of doing this? The $<$ bit of this symbol is bold when I put it into a document, which is less than ideal... May 9, 2012 at 15:36
• @user1729 Maybe a follow-up question with a minimal example is better. May 9, 2012 at 15:38
• I was contemplating asking a new question, but I thought I would ask briefly here first. What do you mean by "a minimal example"? May 9, 2012 at 15:43
• An example of a .tex document that exhibits the problem, including all necessary packages. Don't forget a link to this question. May 9, 2012 at 15:50
• I think I'll wait until I've got a printed out a copy of the document before asking the question - I'm starting to worry it is just my screen playing tricks on me! (Although, for the record, my "minimal example" is exactly what you have written, above.) May 9, 2012 at 15:59