10.3.1 Top new questions this week

10.3.1.1 A subscript that is closer to the tip of the nabla symbol
10.3.1.2 Weird error in custom package instead of the error I tried to throw?
10.3.1.3 expl3's regex_replace_all has a problem with German A~\237, why?
10.3.1.4 What algorithm does LuaLaTeX use for fallback fonts?
10.3.1.5 How to change font inside \DeclareMathOperator?
10.3.1.6 Draw a shape "inside" another one
10.3.1.7 How alter pgfplots 3D surface plot to look better
10.3.1.1 A subscript that is closer to the tip of the nabla symbol

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706290

With the command \nabla_x f(x, y), I have 
I think this is not aesthetic. Is there a way to get the subscript closer to the tip of nabla  symbol? Something looks like 
Thank you so much for your ... 
[subscripts]
 
asked by Akira https://tex.stackexchange.com/landing/r/digest?cta=user&id=161639 Score of 10
answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 Score of 14
10.3.1.2 Weird error in custom package instead of the error I tried to throw?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706486

I am making a custom package for all my personal commands, and I am trying to pass some keyword arguments to the package as described in section 4.4 of clsguide. My use case is that I take math and ... 
[package-writing] [key-value]
 
asked by Shai Avr https://tex.stackexchange.com/landing/r/digest?cta=user&id=274542 Score of 8
answered by Udi Fogiel https://tex.stackexchange.com/landing/r/digest?cta=user&id=264024 Score of 8
10.3.1.3 expl3's regex_replace_all has a problem with German A~\237, why?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706404

EDIT: Solution for this problem below. 
I'm trying to have an in-text direct replacement of entire words, but it seems using regex_replace_all does not work properly as it does not find a word ending ... 
[expl3] [german] [l3regex]
 
asked by learex https://tex.stackexchange.com/landing/r/digest?cta=user&id=218587 Score of 7
answered by Ulrike Fischer https://tex.stackexchange.com/landing/r/digest?cta=user&id=2388 Score of 7
10.3.1.4 What algorithm does LuaLaTeX use for fallback fonts?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706656

Background 
I have been busy with a book about the worlds scripts and languages on and off for a couple of years. It covers all the listed scripts in unicode, as well as a dozen or so, where there is ... 
[luatex] [luaotfload]
 
asked by yannisl https://tex.stackexchange.com/landing/r/digest?cta=user&id=963 Score of 6
10.3.1.5 How to change font inside \DeclareMathOperator?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706437

LaTeX friends. I need to change the font inside \DeclareMathOperator, but my initial attempt failed, as the example below shows. How can I achieve the desired result? 
\documentclass{article} 
\... 
[fonts] [amsmath] [math-operators]
 
asked by Gonzalo Medina https://tex.stackexchange.com/landing/r/digest?cta=user&id=3954 Score of 6
answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 Score of 6
10.3.1.6 Draw a shape "inside" another one

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706667

I'd like to draw a shape (with right only angles) inside another (with only right angles). The edges should be as close as possible without overlapping. 
I can do something by hand, as follows: 
\... 
[tikz-pgf] [diagrams]
 
asked by ClA~(c)ment https://tex.stackexchange.com/landing/r/digest?cta=user&id=34551 Score of 5
answered by Zarko https://tex.stackexchange.com/landing/r/digest?cta=user&id=18189 Score of 7
10.3.1.7 How alter pgfplots 3D surface plot to look better

https://tex.stackexchange.com/landing/r/digest?cta=question&id=706179

I want to use TikZ/pgf to produce the following 3D graphic, which consists of: 
a plot of the function f(x, y) = x y/(x^2 + y^2) when (x, y) != (0,0) and f(0,0)=0; 
the intersection of the plane y = x ... 
[tikz-pgf] [pgfplots]
 
asked by murray https://tex.stackexchange.com/landing/r/digest?cta=user&id=13492 Score of 5
answered by Daniel N https://tex.stackexchange.com/landing/r/digest?cta=user&id=218261 Score of 4