I am working on an electronics for scientists and engineers book that uses the ~ to indicate “poorly approximates”. I have searched for a rule that governs how to space this symbol for the following expression. ~1 mA < |I| < ~10 mA
The logical operator symbol for ~ means “not” which is not how this is being used so I am unsure if this is to be treated as a sign of comparison like a normal double tilde approximation symbol is.
I don’t think that this single tilde is being used as a comparison sign since, in the second instance in this example, it follows a “less than” sign. This tilde means “approximately” much in the same way the tilde means “not” in logic. (It is a qualifier here, not a sign of comparison.) I would braille it unspaced from the number to which it applies.
If there is no space between the tilde and the following number it does not meet the criterion for requiring a numeric indicator. The number is not preceded by a space (or by a space and minus sign).