Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

The notation I've used is $a$~$b$, but one of my teachers said that the correct notation was $a\approx b$. Is this notation really used, and if so, are there any uses of this in literature? I haven't found any.

He also says that $a\approx b$ can't be used for, "approximately equal to $b$" for this reason, and instead, $\dot{=}$ should be used, but I don't think this is true ("\approx" is the latex notation for $\approx$), and I can't even find any uses of $\dot{=}$ online! This wikipeda page has a similar symbol at the bottom, saying that a similar one is commonly used in Japan and Korea.

(This was in a class which has absolutely nothing to do with asymptotic anything, so it isn't notation used in-class during the semester.)

share|cite|improve this question
It could be possible that your school's math department has chosen a convention and taken care that all of your classes are consistent with it, and thus assuming students should be learning that convention as well. – Hurkyl Feb 15 '13 at 6:19

Your teacher has very rigid thinking in this respect. For example, the symbol $\approx$ is named "approx", so a lot of people obviously think it means "approximately". Also, the symbol $\sim$ is used in many places for an asymptotic relation. Specifically,

$$f(x) \sim g(x) \: (x \rightarrow x_0) \implies \lim_{x \rightarrow x_0} \frac{f(x)}{g(x)} = 1$$

See, for example, Bender & Orszag.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.