Im looking for a linear algebra textbook that meets two criterion:   The book should be proof-based.  The book should try and motivate most, if not most of the ideas, of the geometry of linear maps and matrix decompositions. For example, the permutation maps can be thought of as rotation maps because permutation matrices simply rotate the basis vectors. I’m looking for a book that explains all ideas and methods geometrically as well. A plus would also be that the book also foreshadows which properties can be generalized to a functional analytic setting.
I plan to self-study linear algebra this summer. I am sorta already familiar with vectors, vector spaces and subspaces and I am really interested in everything about matrices (diagonalization, ...), linear maps and their matrix representation and eigenvectors and eigenvalues. I am looking for a book that handles every of the aforementioned topics in details. I also want to build a solid basis of the mathematical way of thinking to get ready to an exciting abstract algebra next semester, so my main aim is to work on proofs for somehow hard problems. I got Lang's "Intro. to Linear Algebra" and it is too easy, superficial.  Can you advise me a good book for all of the above? Please take into consideration that it is for self-study, so that it' gotta work on its own. Thanks.
Error on Ubuntu boot up - "recovering journal" Trying to figure out what this means:    I got into the GRUB menu, chose Advanced Options, boot in recovery mode, login as root, and I did:  root@xps:~# sudo fsck -f / fsck from util-linux 2.27.1 e2fsck 1.42.13 (17-May-2015) /dev/nvme0n1p2 is mounted. e2fsck: Cannot continue, aborting.   Coincidentally, I am also seeing this fuzzy rainbow thing on the outside of desktop windows:    But now the machine won't even boot up at all. What is the difference between `grep`, `egrep`, and `fgrep`? Can anyone tell me the technical differences between grep, egrep, and fgrep and provide suitable examples?  When do I need to use grep over egrep and vice versa? How to read and understand the java stack trace? Why does ltablex skip a number in captions? The below example presents two tables with an tabularx environment (taken from package ltablex) and a caption. After each tabularx-table, the table counter skips one, as if both the caption and the tabularx environment increase it, while the latter shouldn't.  \documentclass{report} \usepackage{ltablex} \begin{document}  \begin{table} \caption{Caption 1.} % "Table 1" \begin{tabularx}{\linewidth}{|c|} empty table \end{tabularx} \end{table}  \begin{table} \caption{Caption 2.} % "Table 3" \begin{tabularx}{\linewidth}{|c|} empty table \end{tabularx} \end{table}  \end{document}   My reputation doesn't allow me to upload a picture, but the captions are Table 1 and Table 3 respectively. What are the limitations on the Shape Water cantrip? I have been having a discussion regarding the Shape Water cantrip from the Elemental Evil Player's Companion. A friend and I are trying to come to an accurate view of how this spell actually functions.   Some example questions:   Must the targeted water be within a 5 foot cube area, or does it need to be of a volume not exceeding 125 cubic feet? If you shape water that is within a 5 foot cube, can the final shape you animate it to extend outside the cube? Can you cause the shaping to affect ice and snow, or only liquid water? Would you be able to carry a globe of water alongside you over distances?   Really, there are two parts:    What can be targeted by the spell? What are the limitations on the 'shape and animate' portion of the spell?   The answer I am looking for, if possible, would use the language of the spell, possibly with precedent from other game text, to clearly define the limitations of this cantrip. pgfplots fillbetween with multiple curves What is the use of the square brackets [] in sql statements? I've noticed that Visual Studio 2008 is placing square brackets around column names in sql. Do the brackets offer any advantage? When I hand code T-SQL I've never bothered with them.  Example:  Visual Studio:  SELECT [column1], [column2] etc...   My own way:  SELECT column1, column2 etc... Is Dirichlet function Riemann integrable? Log-transformed variable is not significant, while variable itself is I'm doing a Logistic Regression on company level using the total assets to control for company size. Due to the skewedness of the data, I do a log-transformation of the asset data. While I get no significance for the log-transformed variable, the not transformed variable is highly significant (p &lt; 0.01). What could be a possible explanation of such a result? Does it mean that the relationship is not diminishing for extremely high and low values or does it show an outlier problem and should not be used for interpretation of the data. What Hogwarts classes are taught to two houses at once? In the small amount of physics that I have learned thus far, there seems to be a (possibly superficial pattern) that I have been wondering about.  The formula for the kinetic energy of a moving particle is $\frac{1}{2}mv^2$.  The formula for kinetic rotational energy is $\frac{1}{2}I\omega^2$.  The formula for energy stored in a capacitor is $\frac{1}{2}C \Delta V^2$.  The formula for energy delivered to an inductor is $\frac{1}{2}LI^2$.  Finally, everyone is aware of Einstein's famous formula $e=mc^2$.  I realize there are other energy formulas (gravitational potential energy, for example) that do not take this form, but is there some underlying reason why the formulas above take a similar form? Is it a coincidence? Or is there a motivation for physicists and textbook authors to present these formulas the way they do? Short Story: Army investigates barrier and house I am trying to identify the author and title of a short story with the following plot.  A scientist narrates a story where s/he is called in to help the army investigate an unexplained phenomena.  The army has cordoned off an area where a prairie home has appeared. It is surrounded by a dome that allows things to enter but not to leave. Briefing the scientist, the Army explains that it appears that it is a family of five with mother, father, son, daughter, and grandfather. They look completely normal and live an idyllic life of the 40s or 50s.  They continue to send probes in to investigate the dome and its proprieties. Not sure if this a time anomaly or another dimension.  An Army lieutenant, so enamored by their life runs through the barrier to join the family. The Family faces split into an unnaturally wide smile full of sharp teeth runs towards him and tears him to pieces &amp; eats him. The grandfather then looks up acts as if he can see the forces gathered outside the barrier. He then retrieves a book and it looks as if he reads it out loud and the house and barrier disappear. The narrator worries that the aliens will return. Why does the image not appear? I'm using IEEEtran to format an article, and I wanted to include an image. I included the graphicx and hyperref packages, and used the following code, like normal, to include an image.  \begin{figure}[!t] \centering \includegraphics[width=3in]{fetch} \caption{Pipeline: Fetch Instruction} \label{fig:fetch} \end{figure}   What appears, however, is this:    Fetch.png is a file in the directory, and if I remove it, pdflatex errors instead of producing an output. I'm using MiKTeX 2.9 on Windows 7. Any ideas? Tool for cleaning LaTeX code Is there something like indent for LaTeX? I have a collaborator that is using Scientific Workplace and the code it produces is totally messed up; I know I shouldn't expect miracles, but any machine support would be useful.  EDIT: This question is quite undefined without my comment to KeithB's answer; the idea is to save VC-friendly one sentence/one paragraph per text file line structure which SWT "fixes" by wrapping everything into fixed column width format. I've got Ubuntu 10.10 installed to use my whole hard-disk, but would like to use the 130GB of free space I've got to create a new partition and do some development on Unity and Natty.  Can I use gparted to do this?  If so how? There are many documentaries, forums, blogs and more dedicated to . I have been frantically searching for an answer to my question however none of my sources have clarity to the matter of hand. I would really love a clear explanation to: What exactly is Dark Matter? Please help me to have a clear understanding. (already output) in Debug logs I am trying to add a list into an another nested list before adding values of a list to nested list it is getting the correct value but after adding i am getting (already output) in debug log when i checked.    public List&lt;String&gt; fieldName {get;set;}  public List&lt;List&lt;String&gt;&gt; fileValuesXML; // To get the field values of xml  for(Dom.XMLNode child : SalesforceObjecet.getChildElements()) {                        objecetName = child.getText();             system.debug('Object Name in XML field  ' + objecetName );              for(Dom.XMLNode subchild : child.getChildElements())              {                 system.debug('Sub child ' + subchild.getText() );                 for(Dom.XMLNode subchildfield : subchild.getChildElements())                 {                     system.debug('Sub child Field ' + subchildfield );                     fName  = subchildfield.getText();                     fieldName.add(fName);                     //fileValuesXML.add(fieldName);                     //system.debug('Filed Name in XML field  ' + fieldName);                 }                  system.debug('Filed Name before affing to filevalueXML  ' + fieldName);                                     fileValuesXML.add(fieldName);                 fieldName.clear();                 system.debug('Filed Name after affing to filevalueXML  ' + fileValuesXML);             }    }    I am getting values in debug log as:     Filed Name before affing to filevalueXML  (AccountSource, field3)   Filed Name after affing to filevalueXML  ((), (already output),   (already output)) QGIS creating a fixed distance buffer over selected areas not the entire layer what im doing is making a fixed distance buffer and it's working splendidly but i need the buffer to be created over certain selected areas not the entire layer, and at the creation wizard is only offers the the option of selecting the entire layer, and i need some areas within that layer to have a different buffer and some none at all.  is there a way around that? Is there a word for four times as much, analogous to once, twice, and thrice? How do I make a floor plan with specific dimensions? This is my very first time of using blender. I've tried several tutorials but can't find anything that tells me how to do the very basic thing i want to do.  I simply want to draw a floor plan for a room which is 13 feet by 11 feet and make it 3d so that ultimately i can play with where things go in that room.  Can anyone take me through the steps needed to do this?   I will be so grateful.  Thank you in advance