@RyanG @MartinSleziak: I use braces as well. I also improve the spacing like this: $∀x{∈}S\ ∃y{∈}T\ ( \ Q(x,y) \ )$.

@user21820 Just to be sure: the backslash merely adds a space within the dollar-sign environment, right? If so, what an awesome general tip! THANKS! Secondly, in mathjax, is there a qualitative difference between spelling out the code e.g., \forall versus simply pasting in the character ∃?

My guess is that it would look the same. Differences might be what people searching for such expressions get.

But it would probably better to have this confirmed by somebody who knows more about this.

@RyanG You could also check whether you find something about this in the posts tagged mathjax+unicode on our meta and elsewhere.

@MartinSleziak Good point. I would hope that searching for \exists and ∃ would return identical results.

@user21820 Visually, i cant tell the difference between \ and \, (the latter is what i usually type to insert a minimal gap). is there actually any? i know that \: and \;insert progressively larger gaps.