1.2.1 Top new questions this week

1.2.1.1 Why do PDF files produced by pdflatex not pass validation?

http://tex.stackexchange.com/questions/256952/why-do-pdf-files-produced-by-pdflatex-not-pass-validation

Why do simple PDF files compiled with pdflatex contain so many PDF errors? 
The simplest example I can see is "Hello World!" that once compiled, 
\documentclass{report} 
\begin{document} 
Hello  ...
 

- asked by Paulo Ney (37 votes), answered by Heiko Oberdiek (48 votes)

1.2.1.2 "  shortcut no longer available in babel?

http://tex.stackexchange.com/questions/256740/shortcut-no-longer-available-in-babel

In the answers to this question, people recommend using the "babel shorthand" command "| to break the ligature in the word shelfful. Am I doing this wrong or is this command no longer available in  ...
 

- asked by Andrew Cashner (15 votes), answered by Herbert (12 votes)

1.2.1.3 Is `\hspace*` equivalent to `\strut\hspace`?

http://tex.stackexchange.com/questions/257477/is-hspace-equivalent-to-strut-hspace

Is using \hspace* essentially the same as \strut\hspace? 
The description at \hspace vs. \hspace* seems to suggest that this may be the case, but I was wondering the cases where they might differ.
 

- asked by Brian M. Hunt (11 votes), answered by Herbert (8 votes)

1.2.1.4 How to delay expansion

http://tex.stackexchange.com/questions/257020/how-to-delay-expansion

Consider the following document: 
\documentclass{article} 
\usepackage{polynomial} 
\begin{document} 
\def\a{-3} 
\def\b{-2} 
\def\c{-4} 
\[ 
\polynomial{\a,\b,\c}\quad\polynomial{-3,-2,-4} 
\] 
...
 

- asked by Gonzalo Medina (10 votes), answered by egreg (9 votes)

1.2.1.5 How to make underbrace label text wrap at brace width?

http://tex.stackexchange.com/questions/256894/how-to-make-underbrace-label-text-wrap-at-brace-width

Is there a way to make underbrace label text automatically wrap at the underbraces width, preferably even with automatic syllabication? 
Example where brace label text exceeds underbrace width: 
...
 

- asked by norritt (10 votes), answered by Ruben (13 votes)

1.2.1.6 Parameters in a caption

http://tex.stackexchange.com/questions/257010/parameters-in-a-caption

I have a simple figure with a code like this: 
\begin {figure}[htbp] 
\centering 
% 
\begin{tikzpicture} [scale=1] 
\def \r {1/4} % y-scaling 
% 
% PARAMET. 
\def \a {1}   %x^6 
\def \b {-6}  ...
 

- asked by Emilio Novati (9 votes), answered by Gonzalo Medina (8 votes)

1.2.1.7 Making an anti-clockwise circled arrow around a + sign in a math environment

http://tex.stackexchange.com/questions/257439/making-an-anti-clockwise-circled-arrow-around-a-sign-in-a-math-environment

\makeatletter 
\newlength\@SizeOfCirc% 
\newcommand{\CricArrowRight}[1]{% 
\setlength{\@SizeOfCirc}{\maxof{\widthof{#1}}{\heightof{#1}}}% 
\tikz [x=1.0ex,y=1.0ex,line width=.15ex, draw=black]% 
\draw  ...
 

- asked by user82745 (8 votes), answered by hbaderts (10 votes)