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I wan to know how this letter O with a vertical line for operator null in maths. Thanks.

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marked as duplicate by Werner, CarLaTeX, Sebastiano, Marcel Krüger, ebosi Mar 11 at 21:33

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  • 2
    \mathds{O} from dsfont package. – CarLaTeX Mar 11 at 21:07
  • thanks so much, just what i need it – user89940 Mar 11 at 21:14
  • Hi! Your question is likely to be closed, as it has a relevant answer posted in another thread. Don't take it personally: it's just because it makes this site much more relevant! – ebosi Mar 11 at 21:33

\mathds{O} from dsfont package.

Easy to find on Detexify:

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