TITLE: How to search the internet for strings that consist mostly of math notation?
QUESTION [37 upvotes]: Is there a trick to search the internet for math notation?  For example what if I want to search the internet for "X / ~" ?  The default google search is useless for this and for similar searches where most of the search characters are not letters or numbers.  Google code search allows this kind of search within source code, but this service will shut down in a few months and anyway it searches only source code not math.

REPLY [3 votes]: A few years ago we developed the search engine SearchOnMath, in order to search for mathematical formulas. Recently our tool has indexed both: Mathematics and MathOverflow.
Currently, SearchOnMath is the mathematical search engine with the largest number of indexed sites (including Wikipedia, Wolfram MathWorld, among others ...).
EDIT:
We released on September 2021 a Beta version for arXiv, available at searchonmath.com/arxiv.
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