I am using the XeTex typesetting system on a Macintosh running Snow Leopard. I would like it to produce a PDF/X file. Is this possible? I am mainly concerned with ensuring the fonts are embedded.
Solution  Full solution for producing PDF/X compliant document can be found in MWE and answer to this question:   Adapted MWE and compilation method are taken from Leonid's answer to this question.  Please note that solution requires compilation with TeXLive 2015 (or later).  Original question  I am trying to compile my source with XeLaTeX to produce PDF/X-1a:2001 compliant document. Getting PDF/X-1a:2001 is possible with pdfx package (while using up-to-date TeX distribution), but only when document is compiled with pdflatex.  Since I am using OTF and TTF fonts in my document, I have to use XeLaTeX to compile it. This is MWE:  \documentclass{book} \usepackage[x-1a1]{pdfx} \begin{document} Some text \end{document}   When I try to compile this document with MiKTeX's 2.9 xelatex I get following error and compilation halts:  ! Undefined control sequence. l.111 \pdfminorversion                       =4 %  assumed for PDF/A ;  options may change this for...  ?    Is there any way to compile PDF/X-1a:2001 with XeLaTeX, either using pdfx or different package?  Ps. I used MiKTeX 2.9, because I don't want to update my TeX Live 2013/Debian distribution I normally use. With MiKTeX I get most recent version of pdfx package.  EDIT: Since it isn't obvious from Leonid's answer and is mentioned only in comments, please note that you need TeXLive 2015 in order for Leonid's answer to work fully. TeXLive 2013 (installed by your system's package manager) or MiKTeX 2.9 won't do the trick (this is true as of March 2016; it might change by the time you read this).    I also tried to compile this MWE with LuaLaTeX to see if this works. It didn't. I get following error:  ! Undefined control sequence. \pdfx@findUUID ... \pdfx@tmpstring {\pdfmdfivesum                                                    {#1}} \expandafter \pdfx@e... l.360 \pdfx@findUUID{\jobname.pdf}  ?   In the event version of LuaLaTeX matters: lualatex --version outputs  This is LuaTeX, Version beta-0.76.0-2013062821  (MiKTeX 2.9 64-bit) (rev 4627)
A clock in freefall Time dilation  using Schwarzschild metric for a non rotating spherical body is: $$t_0=t_f\sqrt{1-\frac{2GM}{rc^2}}$$  For such a non rotating spherical body, what would the time dilation of a clock in vacuum free-falling from infinity be?  (If the answer is non-trivial; a high level outline of the calculation would suffice / be appreciated)  Edit: I am currently working on an iOS app that is trying to model the mechanism underpinning relativity.  So, far the mechanism that I have created is shockingly simple and shockingly good at conforming to Relativity.  However, I am trying to break it.  I am trying to find any possible areas where the two may diverge.  I have noted that using my model a clock in freefall will experience no time dilation, i.e. $t_0=t_f$ and I want to make sure Relativity agrees.  I have noted the gravitational component of time dilation above.  Since my clock is moving one might also expect a kinematic time dilation.  I can calculate the velocity of my clock: $$E_k=\frac{1}{2}mv^2$$ $$E_p=\frac{-GMm}{r}$$ $$v=\sqrt{\frac{2GM}{r}}$$ Plugging this velocity into the kinematic time dilation equation: $$\Delta t'=\frac{\Delta t}{\sqrt{1-\frac{v^2}{c^2}}}$$ $$\Delta t'=\frac{\Delta t}{\sqrt{1-\frac{2GM}{rc^2}}}$$  At this point one might make the observation that the kinematic dilation is the inverse of the gravitational dilation and therefore conclude that: $$t_0=t_f$$ Sum of reciprocals of numbers with certain terms omitted Including the interaction but not the main effects in a model Assign z values to depth curves in QGIS I'm new to QGIS and working with GIS in general (student of architecture), so please bear with me.  I have obtained shapefiles with topographic curves of an ocean floor. My intention is to export these as CAD files and render as 3D models of the ocean floor in Revit. I have done this procedure earlier with terrain shapefiles. My problem now is that these files mapping depth does not contain z values, so when exporting them into CAD they are completely flat rather than 3D models.  The depth information in meter exists as attributes in the file (see attached image). What I want is to transform this depth value into real z coordinates for each line so that the curves have different heights when importing as CAD file in Revit.  Thankful for any pointers in the right direction. If $A$ is a square matrix and $A^2 = 0$ then $A=0$. Is this true? If not, provide a counter-example. This is a proof question and I am not sure how to prove it. It is obviously true if you start with $A = 0$ and square it.   I was thinking:  If $ A^2 = 0 $  then $ A A = 0 $  $ A A A^{-1} = 0 A^{-1}$  $I\,A = 0 $   but the zero matrix is not invertible and that it was not among the given conditions.  Where's a good place to start? Show $f(x)=x\ln x$ is not uniformly continuous Show $f:(0,\infty)\rightarrow \mathbb{R}, f(x)=x\ln x$ on $(0,\infty)$ is not uniformly continuous.    I think that the general way to prove that something is not continuous in a metric space is to let $\epsilon=...$ and show that $\forall\delta&gt;0$, $d&#39;(f(x)-f(y))&gt;\epsilon$. I can't use the Mean Value Theorem because we haven't gone over it yet.    Here's an attempt: Let $\epsilon=1$. Without loss of generality, let $x&gt;y&gt;0$. $|x\ln x-y\ln y|&lt;|(x-y)(\ln x)|\leq|x-y||\ln x|$...$\delta=\frac{\epsilon}{\ln x}$ and therefore doesn't work for all $x$? Problem: Let $f$ be defined for all real $x$, and suppose that   $$|f(x)-f(y)|\le (x-y)^2$$  for all real $x$ and $y$. Prove $f$ is constant.  Source: W. Rudin, Principles of Mathematical Analysis, Chapter 5, exercise 1. In the case of a non-inverting amplifier, if I DC couple the input signal with a capacitor only, \$C_1\$ (i.e. no resistor to ground), sources (as well as an experiment in the lab) show me that the op amp input will be saturated as the input bias current deposits charges on the terminal without having a return path to ground. This is solved by using connecting a resistor (\$R_1\$, as shown in the image below) to ground to create the return path. [The image is reproduced from an answer by "Neil_UK" on one of my previous questions, thanks Neil!]    My questions:   1) How is the input bias current able to continuously deposit charges and saturate the input if I don't use the resistor? The resistor should not allow the DC bias current through, so where is this current flowing from/into?  2) Why is this not a problem for the feedback path to the "-" terminal? There is no resistor to ground in that case, and capacitor \$C_2\$ seems to be causing no issues. The PDFs I've been reading suggest that the feedback behaves similar to when I have a resistor to ground by acting as the return path, how is this? By integration by parts and the substitution $x = \sin t$ we can easily calculate the integral $\int_{0}^{1} \ln (x+ \sqrt{1-x^2})dx$ which equals to $\sqrt{2} \ln (\sqrt{2} +1) -1.$ I’ve tried to use the same substitution $x = \sin t$ to calculate the integral $ \int_{0}^{1} \frac {\ln (x+ \sqrt{1-x^2})}{x}dx,$ which becomes $$ \int_{0}^{\frac {\pi}{2}} \frac {\ln \sin (t+ \frac {\pi}{4})}{\sin t}dt$$ It seems difficult to solve the particular integral. Any help? How do you reopen a closed question? Why did the first Linux developers choose to implement a non-preemptive kernel? Is it to save synchronization?  As far as I know, Linux was developed in the early '90s, when PCs had a single processor. What advantage does a non-preemptive kernel give in such PCs? Why, however, the advantage is reduced by multi-core processors? File permissions and saving How to install and configure Wine? To my knowledge there are three types of acceleration when a body (e.g. a rod) is moving in a circle about an axis. These are:   Angular acceleration : this is the rate of change of angular velocity. Tangential acceleration : this is the linear acceleration of the system in a tangential direction to the circle and equals the radius times the angular acceleration. Radial/centripetal acceleration : this is the linear acceleration of the system that is directed inwards towards the center of the circle.   I also think there are two types of velocity:   Linear velocity: this is its velocity in the tangential direction and is constantly changing Angular velocity or angular frequency: this is the rate of change of angle.   Is the above correct? And have I missed anything? Find all natural numbers $x,y$ such that   $$3^x=2y^2+1$$  solutions are $(1,1)$, $(2,2)$, $(5,11)$. I found that parity of both is same and If $x$ Is odd it is of the form $4k+1$. How can i disable totally the prompts that appear while installing a Debian package, i've used all the options that i've found but there are some packages that are still prompting.  I'm using this command:  apt-get -y --allow-unauthenticated --force-yes -o DPkg::Options::="--force-overwrite" -o DPkg::Options::="--force-confdef" install x11-common   Why the x11-common package is still prompting? how can i get rid of these prompts?  Thanks in advance  --Victor  Edit: just to clarify, the prompts are not "yes/no" prompts, are open questions in a coloured screen (typical two color screen) but i want to set the default option of these questions I'm currently doing a couple of exercises on logarithmic expressions, and I was a bit confused when presented with the following: $5^{\log_5 17}$.  The answer is $17$, which is the argument of the logarithm in the exponent, but I don't understand the reason why.  A previous question in the exercise was $12^{\log_{12} 144}$, which is pretty straight forward since $\log_{12} 144=2$ and $12^2=144$ but since $\log_5 17$ is an irrational number, I couldn't calculate it the same way.  So my question is, why is $x^{\log_x n}=n$?  [Update]  I've now managed to reason this out and realized how simple it is.  Basically, if $y=\log_x n$, then $y$ is the number that  $x$ must be raised to to become $n$; therefore, if I raise $x$ to that power $y$, I will naturally get $n$.  I guess my problem was that I tried to work out the question mechanically instead of intelligently and that's why I failed, because once I realized that I can't calculate $\log_5 17$, I was stumped.  Now that I reasoned it out, as explained in the previous paragraph, I understand it. Cross tabulation of two categorical variables: recommended techniques Is there a Stack Exchange site for both technical and behavioural interview questions? Where I could ask questions about, for example:   Sample questions and solutions, experiences, or seeking advice for interviews A place where I could ask interview questions and what the best way to answer it (not just a correct way or the most efficient).   What to do in a certain situation such as negotiation, unfair interviews, etc.   Experiences interviewing at so-and-so company. How to remove Firefox's "inspect element" button? This is driving me crazy! When FF 12 came out, Firefox's own 'Inspect Element' button on the right-click menu took the place of there the Firebug 'Inspect Element' button used to be.  As I've been doing web development in Firefox forever, my muscle memory still clicks there when I want to use Firebug.    Is there any way to remove the Firefox internal 'Inspect Element' and replace the button on the menu with Firebug's, returning it to its original position (marked NO in the screenshot)?