6

When writing that two objects are isomorphic, I use X \cong Y.

Sometimes however, it is necessary to specify the type of isomorphism in question. I wish to do this with text above/below the isomorphism symbol, in much the same way that one can use \xrightarrow{} to insert text above an arrow indicating a map from X to Y.

Using X \cong_{text} Y or X \cong^{text} Y doesn't do exactly what I want, because this gives me subscript/superscript, which are offset from the \cong symbol. What I want is text that appears directly above/below the isomorphism symbol, like \xrightarrow.

What can I do to make that happen?

1

1 Answer 1

10

Like this?

enter image description here

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb}

\begin{document}

$A\overset{a}{\cong}B, c\underset{b}{\cong}D$

\end{document}

It is possible to use \text from amsmath.

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb}

\begin{document}

$A\overset{\text{over}}{\cong}B, c\underset{\text{under}}{\cong}D$

\end{document}

enter image description here

2
  • 1
    Like that indeed. Thank you :)
    – Matt
    Sep 22, 2020 at 13:11
  • @Matt It has been a pleasure to help you. :-) If you need us, we are all here to help you.
    – Sebastiano
    Sep 23, 2020 at 8:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.