Pdf Tricks on Arch

Here're some more arch tips and tricks so I don't forget them.

Merge Pdfs into one big Pdf:

Using ghostscript this is pretty easy (ghostscript is part of a standard Tex install):

$gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=file.pdf Input1.pdf Input2.pdf Input3.pdf

Problems, the metadata for the new file will be that of the last file, if this needs to be changed there's a way.

Changing Metadata for Pdf's on Arch Linux

Using exiftool this isn't too bad, bugs with paths associated with exiftool seem to have been fixed, and it's in the official repository (perl-image-exiftool).

$exiftool -Title="Title" -Author="Author" -Subject="Subject" file.pdf

Note that this creates a new file called file_original.pdf, which is surprisingly enough the original file. The modified version will be file.pdf.

Also for information on which tags are present use:

$exiftool file.pdf

Good Start to a Day.

10 foot Strides

Here're some photos from my first day with my new toy. I ordered a nimbus nightfox 36 in hopes of doing some unicycle touring on it this summer, specifically the goal is a 100 mile one day ride out to the boiling river in Yellowstone.

Some initial thoughts:

• It starts, stops, and turns slower than a 24. Specifically the stopping was a bit surprising.
• The top speed on the outer hole of the cranks seems to be about 10 miles an hour. Perfect for touring (I hope.)
• The handlebars make a world of difference. I rode 25 miles without them and was pretty sore, with them on it feels like you could ride forever.
• Disc brakes are different to set up. I'm going to swing by Altercycles this afternoon and get some help tweaking them.
• People still love a guy on a unicycle. My first stoplight experience ended with me landing on the hood of a Subaru (hopping is different). The owner's reaction was "I love your unicycle".

Video from Saint George

Here's some video of the "Barrel Roll" trail in St. George. The rider is Rees, a math student at Dixie.

Lick Creek

Some scenery shots from skiing up Lick Creek on Sunday. This short little meadow is a great deal of fun and is pretty free of avalanche hazards (~30 degrees). East aspect and knee deep powder made for some great runs.

 

include{} and input{} in Latex

This is just a quick note on the differences between the commands include{} and input{} in Latex. Both of them have essentially the same function: read some tex from a separate file to make writing large documents easier in Latex. There are some key differences.

Note: 

• with my setup neither command will work unless you leave off the .tex extension.
• include{} has a \clearpage before and after it.

include{} is best used to include something like a chapter. In other words the file should be almost all of a stand alone document. It shouldn't include a \begin{document} or an \end{document}, headers, footers, or package inclusions. It should be noted that commands which have filepaths in them are referenced from the location of the file being executed, not the included file.

input{} is best utilized for importing the enormous list of \usepackage and custom commands that everyone seems to have at the top of their tex documents.

For example we might have a file system which looks like this:

• example.tex
• Images
• exampleimage.png
• Chapter1
• chapter1.tex
• Preamble
• preamble.tex

example.tex

\input{Preamble/preamble}

\begin{document}

This is my example document...

\include{Chapter1/chapter1}

\end{document}

preamble.tex

\documentclass[a4paper,11pt]{article}

\usepackage[utf8]{inputenc}

\usepackage{default}

\usepackage{amssymb}

\usepackage{graphicx}

chapter1.tex

\section{Chapter One}

This is the first chapter...\\

Here's a picture:\\

\includegraphics{Images/exampleimage.png}

Which generates this pdf.

Shishikura's Lemma 3

In keeping with Sam's demand for more nerdy code, I've decided to provide a chunk of my thesis for the perusal of randoms from the internet. This link leads to a short paper I've written detailing the proof of a result I need for my result. The result itself is Lemma 3 found in the perturbation section of a paper called 'On the Quasiconformal Surgery of Rational Functions' by Mitsuhiro Shishikura.

The cones in the sketch correspond to the striped regions in this picture. The green circles are level curves in Siegel disk. Exactly which functions can give rise to such a disk is the topic of my research.