The "equivalence" symbol ($\equiv$) works well, while the "crossed" versions, like $\neqiv$ and $\notequiv$, do not ?

Some alternatives ?


  • $\begingroup$ Generically one can put \not in front of relational symbols, so $\not\equiv$ may suit you. $\endgroup$
    – hardmath
    Commented Sep 14, 2017 at 4:25

1 Answer 1

  • \not\equiv$\not\equiv$
  • if you want to adjust the position of the slash, you can do $\not\!\equiv$ or $\not\,\equiv$ by adding a negative thinspace \! or a thinspace \, between \notand \equiv
  • 3
    $\begingroup$ Back in PlainTeX -era some of us created a "blackboard bold R" by adding a suitable amount of negative thinspaces between "I" and "R". $\endgroup$ Commented Sep 13, 2017 at 15:44
  • $\begingroup$ This is a very cool trick, and how did you managed $\Bbb Q$ ? $\endgroup$
    – Surb
    Commented Sep 13, 2017 at 19:11
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    $\begingroup$ By using negative space, you could also do \equiv\!\!\!\!\!/, and adjust the amount of spaces you want from that. $\endgroup$ Commented Sep 13, 2017 at 22:23
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    $\begingroup$ You should use the first solution, \not\equiv, and not play around with the spacing. This will provide the proper unicode symbol (U+2262), whereas the others will not. Why is this important? Because it will help people who need assistive technology (like screen readers) to get the proper rendering of the mathematics. The other suggestions will produce gibberish. Also, the U+2262 has the slash properly placed, so there is no need to adjust it. Please don't use the suggestions that include \! or \,. $\endgroup$ Commented Sep 14, 2017 at 0:36
  • $\begingroup$ Thanks for the explanation @Davide. As we see from the output in this case it would be silly to adjust the spacing. Such dirty tricks were not uncommon in the past. To all: Even today thinspace is commonly added to integrals, because TeX has no way of knowing that $dx$ is not a product of $d$ and $x$. $$\int_a^bf(x)\,dx\qquad\text{vs.}\qquad\int_a^bf(x)dx.$$ $\endgroup$ Commented Sep 14, 2017 at 5:37
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    $\begingroup$ @JyrkiLahtonen, thanks for your example. Certainly use space where it is appropriate and needed, like this (this space won't interfere with screen readers). My suggestion was to try to avoid it where it is used to make something that looks like a particular character, but really isn't. $\endgroup$ Commented Sep 14, 2017 at 9:50

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