What is the easiest way to superscript in text mode or outside of math mode?
What is the easiest way to superscript text outside of math mode?  For example, let's say I want to write the $n^{th}$ element, but without the math mode's automatic italicization of the th.  And what if I still want the n to be in math mode, but the th outside?
What is the purpose of LongLength for .Net Arrays? Is it possible for information to be transmitted faster than light by using a rigid pole? Is it possible for information (like 1 and 0s) to be transmitted faster than light?   For instance, take a rigid pole of several AU in length. Now say you have a person on each end, and one of them starts pulling and pushing on his/her end.   The person on the opposite end should receive the pushes and pulls instantaneously as no particle is making the full journey.  Would this actually work? I try unsuccessfully to install the ECW support (mainly to use ECW file in QGIS 2.2). We attempt to follow and adapt the howto provided by .  My first supprise was the repository ubuntugis-unstable is unavailable for trusty and the repository  doesn't have libgdal-ecw-src package. Finally in desperation we add ubuntugis-unstable for the raring distribution in source.list.  And apply the following commands   chmod +x ERDAS-ECW_JPEG_2000_SDK-5.1.1.bin ./ERDAS-ECW_JPEG_2000_SDK-5.1.1.bin # Select option desktop read only sudo cp -r ERDAS-ECW_JPEG_2000_SDK-5.1.1 /usr/local/ sudo ln -s /usr/local/ERDAS-ECW_JPEG_2000_SDK-5.1.1/Desktop_Read-Only/lib/x86/release/libNCSEcw.so /usr/local/lib/libNCSEcw.so sudo ldconfig sudo apt-get install libgdal-ecw-src sudo gdal-ecw-build /usr/local/ERDAS-ECW_JPEG_2000_SDK-5.1.1/Desktop_Read-Only   The ECW format seems to be installed  gdalinfo --formats | grep -i ecw   ECW (rw+): ERDAS Compressed Wavelets (SDK 5.1)   JP2ECW (rw+v): ERDAS JPEG2000 (SDK 5.1)   But .... Gis crash when a ECW raster file is open with the following message :   QGIS died on signal 4Abandon (core dumped)   If anyone have an idea Q&A Identification of seldom man-made physical objects not being piece of art? Is SE Q&amp;A format relevant for "identification of seldom physical objects observed in real world"?  Questions like "I do not know function of this object (picture) - which purpose does it have?"  In many cases I suppose these question could have civil engineering or handcraft i.e. cultural/historical background. In second case "SE history" might be okay. For first case, I do not know. Can I set max_retries for requests.request? Under which assumptions a regression can be interpreted causally? First, don't panic. Yes, there are many similar question on this site. But I believe none gives a conclusive answer to the question below. Please bear with me.  Consider a data generation process $\text{D}_X(x_1, ... , x_n|\theta)$, where $\text{D}_X(\cdot)$ is a joint density function, with $n$ variables and parameter set $\theta$. It is well known that a regression of the form $x_n = f(x_1, ... , x_{n-1}|\theta)$ is estimating a conditional mean of the joint distribution, namely, $\text{E}(x_n|x_1,...,x_{n-1})$. In the specific case of a linear regression, we have something like $$ x_n = \theta_0 + \theta_1 x_1 + ... + \theta_{n-1}x_{n-1} + \epsilon $$ The question is: under which assumptions of the DGP $\text{D}_X(\cdot)$ can we infer the regression (linear or not) represents a causal relationship? It is well known that experimental data does allow for such interpretation. For what I can read elsewhere, it seems the condition required on the DGP is exogeneity: $$ \text{E}(x_1, ... x_{n-1}|\epsilon) = 0$$ The nature of randomisation involved in experimental data ensures the above is the case. The story goes then to argue why observational data normally fails in achieving such condition, reasons including omitted variable bias, reverse causality, self-selection, measurement errors, and so on. I am however uncertain about this condition. It seems too weak to encompass all potential arguments against regression implying causality. Hence my question above. UPDATE: I am not assuming any causal structure within my DGP. I am assuming that the DGP is complete, in the sense that there must be some causality (an ontological position it could well be debated), and all relevant variables are included. The key is to identify the set of assumptions which ensure me causality goes from certain variables to the other, without assuming from the outset such direction of causality.  Many similar posts on the site spend time mentioning why correlation does not imply causation, without providing hard arguments about when it does. That is the case, for instance, of  very popular post. Additionally, in the  on the site about the topic, the accepted answer gives the very vague answer:  Expose all hidden variables and you have causation.  I do not know how to translate that to my question above. Neither is the second most upvoted answer. And so on. That is why I believe this post does not have an answer elsewhere. How would I solve the following problem involving elementary matrices? Let $A=\begin{pmatrix}0&amp;5\\ 7&amp;4\end{pmatrix}$.      1) Write $A$ as a product of $4$ elementary matrices.      2) Write $A^{-1}$ as a product of $4$ elementary matrices.   My work. I have managed to find $A^{-1}$, which came out to be this:  \begin{pmatrix}-\frac{4}{35}&amp;\frac{1}{7}\\ \frac{1}{5}&amp;0\end{pmatrix}  However, I am struggling to figure out how I would split each of these matrices into $4$ elementary matrices. Any help? Tracking down where disk space has gone on Linux? When administering Linux systems I often find myself struggling to track down the culprit after a partition goes full. I normally use du / | sort -nr but on a large filesystem this takes a long time before any results are returned.  Also, this is usually successful in highlighting the worst offender but I've often found myself resorting to du without the sort in more subtle cases and then had to trawl through the output.  I'd prefer a command line solution which relies on standard Linux commands since I have to administer quite a few systems and installing new software is a hassle (especially when out of disk space!) "There Is"/"There are" depends on plurality of the first list element or not? It seems I put a   Bounty assigned by outside party, two lengthy, reference-citing answers, one "-1" (awarded the bounty), one "-2", two others scored "0" and "-2" respectively, the answers suggesting one or the other is correct, 73 comments and no consensus so far - and me, as the asker, lost without a clue what to think of the answers anymore -  this is no longer "Learners' Level" question, so I thought I'd bring it here and hear what the experts have to say.    Original question:  Plurality of verb depending on plurality of list elements  An edit was suggested to my sentence.     There was were an orange, some grapes, two apples and a small pile of cherries on the plate.   In my native language plurality of the verb always follows plurality of the first element on the list. There were an orange,... sounds awkward to me, no matter what follows up. My simple solution was reordering:     There were some grapes, an orange, two apples and a small pile of cherries on the plate.   But that's not the first time I faced this situation and I'd like to know what the rules of grammar say about that - was my editor overzealous or am I trying to copy rules of my language that don't apply in English?    Someone linked a  for negatives, where the situation is more clear-cut ("There is no..."). Same applies to connection with "or" apparently, per accepted answer there. Still, nothing for "and".  It seems there is a consensus that in that if the verb goes after the list, it will be plural.     an orange, some grapes, two apples and a small pile of cherries were on the plate.   There doesn't seem to be clear consensus for:     On the plate { was | were } an orange, some grapes, two apples and a small pile of cherries   Adding more to the confusion is the abbreviated form: "There's"     One last note. In North America, at least, there is a widespread use of using a singular form like "there is" and "there was", without regard for the subject item or items, and this "there is" is often shortened to "there's":           There's three apples on the table!      Could you please clarify this mess? Laptop randomly waking up = Hibernate / Low Battery? Modular exponentiation by hand ($a^b\bmod c$) How do I efficiently compute $a^b\bmod c$:  When $b$ is huge, for instance $5^{844325}\bmod 21$? When $b$ is less than $c$ but it would still be a lot of work to multiply $a$ by itself $b$ times, for instance $5^{69}\bmod 101$? When $(a,c)\ne1$, for instance $6^{103}\bmod 14$?  Are there any other tricks for evaluating exponents in modular arithmetic?  This is being asked in an effort to cut down on duplicates, see  and . Debugging JavaScript in IE7 I need to debug JavaScript in Internet Explorer 7. Unfortunately, its default debugger doesn't provide me with much information. It tells me the page that the error showed up on (not the specific script) and gives me a line number.  I don't know if that is related to my problem. It'd be nice if it could narrow down the error to a line number on a specific script (like Firebug can). Is there an addon to debug JavaScript in IE7 like Firebug does in Firefox? Thank you! See also: I'm  having some trouble editing the content of a Managed Email Template, I can quite easily modify the content of the Email Template, but when I wish to refer to an unmanaged component, like this:  &lt;messaging:attachment renderAs="PDF" filename="invoice.pdf"&gt;     &lt;c:MyComponent/&gt; &lt;/messaging:attachment&gt;   I get the error message:     Error: Unknown component c:mycomponent   Does anyone know if its possible to embed an unmanaged component in a managed Email Template? An exercise of Rudin's Real and Complex Analysis says:     Is it true that every compact subset of $\mathbf{R}^1$ is the support of a continuous function? If not, can you describe the class of all compact sets in $\mathbf{R}^1$ which are supports of continuous functions? Is your description valid in other topological spaces?   I proved that, in every metric space, a set (not necessarily compact) $A$ is the support of a continuous function if and only if it is the closure of an open set.  However, I don't think that this characterization holds for every topological space.  So, in order to find a counter-example, I tried to use the discrete and the trivial topologies. However, the discrete topology is metrizable and this characterization holds for topological spaces with the trivial topology.  Is this result true for any topological space? If not, what would be a counter-example? Hilbert, Gödel, and "God equations" - a 19th century lesson for 21st century physicists? It seems there are a lot of respected physicists appearing on pop-sci programs (discovery channel, science channel, etc.) these days spreading the gospel of   Three examples, quickly: 1) Many programs feature Michio Kaku saying that he is on a quest to find an equation, "perhaps just one inch long," which will "describe the whole universe."  2) Max Tegmark has come out with  in which he expresses the gut feeling that "nothing is off-limits" to science.  The subtitle of this book is My Quest for the Ultimate Nature of Reality.  3) In the series  there is talk about a search for the "God equation."  (A good counter-example would be Feynman, but his self-described "non-axiomatic" or "Babylonian" approach does not seem popular with physicists today.)  Is there any sense among physicists that it might be impossible to articulate the "ultimate nature of reality" in equations and formal logic?  It seems to me that physicists are following in the footsteps of the 19th century mathematicians (led by Hilbert) who were on a similar quest which was put to rest by Gödel's incompleteness theorems in 1931.  Is there any appreciation for how the Incompleteness Theorems might apply to physics?  Has any progress been made on  for the 20th century?  Shouldn't this be addressed before getting all worked up about a "God equation?" Why didn't Spock die in The Search for Spock? How does the Adam method of stochastic gradient descent work? Defining my own command Any good tutorials for learning how to post-process images? I don't really know where to start with post-processing my images. I normally just straighten, crop and sharpen. Do people know of any good resources on the internet for getting a grip with Photoshop and similar tools? Show that the series $\sum\limits_{n=2}^{\infty} \frac {(n^3+1)^{1/3}-n}{\log n}$ converges