Math Double-Closed-Path-Integral Symbol

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1

Hello! My question is quite simple, really. How do I implement a double closed path integral symbol? I am aware of \oint but that’s only a single closed loop integral. I am looking to make some notes on Maxwell’s equations.

It’s this symbol here.

image

Any help is appreciated! I am willing to install plugins.

2

This question is more specific to MathJax than to Obsidian, but nonetheless I’ve done a little bit of research and as far as I can tell this isn’t currently supported.

  • MathJax out of the box only supports symbols that are contained in the amssymb package.
  • \oiint and \oiiint are contained in the following packages (but not in amssymb):
    • esint
    • mathabx
    • tx/pxfonts
    • MnSymbol
    • mathdesign
    • unicode-math
  • MathJax support a series of extensions to enrich its features.
  • But currently Obsidian doesn’t support MathJax extensions.
  • But currently Obsidian doesn’t support a MathJax extension that contians that symbol (extension/package that currently might not exist at all)

There are a bunch of threads here on the forum about MathJax extensions support, maybe you can bump them to keep the request alive.

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There is also a unicode symbol that you can copy and paste: ∯

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We support all extensions that are bundled within the Mathjax distribution. I searched briefly and I haven’t found much outside the MathJax distribution. If they exist(?), they can be added with plugins through the API.

5

Error on my own, I edited my previous reply. I checked the documentation and the third-party plugins repo (that refers to MathJax v2, while probably Obsidian is using v3) and nothing related to the \oiint symbol showed up (even in the physics extension), so basically at the current state of things it can’t be shown in MathJax at all, right?

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With Extended MathJax I put this in my preamble, seems to do the trick (although I suspect how well it renders is very platform-dependent)

\newcommand{\oiint}{\subset\!\supset \!\!\!\!\!\!\!\!\!\!\iint}
7

actually, I now realise a much nicer solution is

\newcommand{\oiint}{{\subset\!\supset} \mathllap{\iint}}

you can even have an \oiiint that doesn’t look half bad

\newcommand{\oiiint}{{\Large{\subset\!\supset}} \mathllap{\iiint}}
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