I don't know if the question is well suited here, but I don't know about a forum dedicated to this search engine, yet since it is widely used by MSE members, I guess that should do it (please redirect me, if not).
One of the main advantage of Approach0 is its internal substitution mechanism, so for instance if you search for $f(x,y)$ it will also search for $f(u,v)$ or $f(a,b)$, etc... bringing results that would not have appeared else, which in general is a good thing.
But in some cases, I have found it to be inconvenient, especially when you search for a specific subject.
For instance, it is good for $i$ to be replaced by $n,k,j$ and so on when the subject is about integer algebra, but I would like it not being substituted when it is the complex $i^2=-1$.
The same goes for $z$ complex, I don't want it to be substituted by $x$ and get all inappropriate answers only valid in the real case.
Most of the time, I workaround it by adding keywords in the search (like complex, integer, etc...) but it is not always efficient.
Is there a way to force a literal expression search in Approach0 ? Like escaping characters of some sort ?
Thanks to Martin Sleziak, effectively the links provided shows a discussion between Wei Zhong and Jykri Lahtonen addressing this very subject.
Here is the quote by W.Z:
But I do agree it may be beneficial to give options to control what level of substitution strictness a specific query wants to apply, although technically possible, my preference is still let search engine work on its side to prioritize better matches at the same time allow more possibilities in results to improve search recall.