First time posting, sorry if my question in the title isn't clear enough. To clarify, I'm trying to put an inequality sign, more specifically the sign > alongside a given Greek letter (alpha) after a given line assumption.

I want to put have something like this, which was done in Word as a draft.

enter image description here

Whereas in LaTeX, the outcome is like this

enter image description here

A sample of my work is as follows

\frac{\partial G}{\partial q} = \mu_z - r_0 - 2\alpha q\sigma_z^2    \label{eq:1.6}
SOC\begin{equation}\frac{\partial^2G}{\partial q^2} | _\alpha >0 = -2\alpha\sigma_z^2 < 0   \label{eq:1.7}
From \ref{eq:1.3} solving for q yields
\mu_z - r_0 = 2\alpha q\sigma_z^2
q = \frac{u_z - r_0}{2\alpha\sigma_z^2}

Notice that the inequality doesn't go underneath with the letter, trying to overcome this but still haven't found a solution.

  • 3
    If a subscript (or superscript) has more than one character, you need to enclose it in braces (e.g. |_{\alpha>0}). Otherwise LaTeX has no way to know where the subscript ends. Jan 10, 2017 at 22:04
  • Also see: tex.stackexchange.com/questions/15894/…
    – Au101
    Jan 10, 2017 at 22:19

1 Answer 1


Put {} around the underscript.

 \frac{\partial G}{\partial q} = \mu_z - r_0 - 2\alpha q\sigma_z^2 \label{eq:1.6}
 \frac{\partial^2G}{\partial q^2} | _{\alpha >0} = -2\alpha\sigma_z^2 < 0\label{eq:1.7}
From \eqref{eq:1.7} solving for $q$ yields
 \mu_z - r_0 &= 2\alpha q\sigma_z^2\notag\\
 q &= \frac{u_z - r_0}{2\alpha\sigma_z^2}

enter image description here

  • ... off-topic: \left.\frac{\partial^2G}{\partial q^2}\right|_{\alpha >0} = -2\alpha\sigma_z^2 < 0 \label{eq:1.7} will give more nice result. By the way, your answer should have form of complete small document ...
    – Zarko
    Jan 10, 2017 at 22:18
  • @Zarko I'd much prefer something like \Big|_{\alpha>0} or \bigg|_{\alpha>0} rather than \left. and \right|.
    – egreg
    Jan 10, 2017 at 22:40
  • for this reason I titled my comment "off-topic" ... :). you solve issue of subscripts!
    – Zarko
    Jan 11, 2017 at 0:15

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