The object I downloaded from internet is covered in black spots. There is no texture or material on it. How can I delete them?
I have imported a mesh (AutoCad DXF) and I'm experiencing strange shading behavior. I've done the following to try and address the problem with no luck:  Recalculate Normals Remove Doubles Delete Loose Geometry Cleared Seam, Sharp, and Bevel Weights  There are no modifiers on the mesh.  The original imported mesh looks fine in smooth shading but I need the mesh to be in quads which causes the shading to mess up as shown in photo. I can add my .blend file but I'm not sure how to do that.
I have created some search entries in Google Chrome using 'Edit search engines'.  How can I share some of these entries with my colleagues? How can a company use money from stock investors when they are constantly being bought and sold? $\mathbb{F}_p[X]/(X^2+X+1)$ is a field iff $p \equiv 2 \bmod 3$ Views indicator inaccurate, shows one views on question with two close votes Two close votes and only one person has viewed the question?    How did this happen? Fancy chapter headings Set the maximum character length of a UITextField How can I set the maximum amount of characters in a UITextField on the iPhone SDK when I load up a UIView? I have a laptop which is connected to the internet with ADSL modem, and I would like to share the internet for any laptop connecting to wireless router from my laptop using hotspot.  This is what I want:  ┌────────────────────┐ │ ADSL modem         │ └───┬────────────────┘     │ ┌───┴───────────────────────┐ │ laptop's wired adaptor    │ │                           │ │ Hotspot software          │ │                           │ │ laptop's wireless adaptor │ └───┬───────────────────────┘     │ ┌───┴──────────────────────┐ │ wireless router(linksys) │ └───┬──────────────────────┘     │ ┌───┴─────────────────────────────┐ │ Laptop computers and cellphones │ └─────────────────────────────────┘   How can I do that? How do I extract text that lies between parentheses (round brackets)? I am trying to prove the following by Mathematical Induction:  $$\sum_{i=1}^n i\cdot i! = (n+1)!-1\quad\text{for all integers $n\ge 1$}$$   My proof by Induction follows: First prove $P(1)$ is true,  $$\sum_{i=1}^1 i\cdot i! = (1+1)! - 1$$  Then, for all integers $k &gt;= 1$, if $P(k)$ is true then $P(k+1)$ is also true,  $$ \sum_{i=1}^k i\cdot i! = (k+1)! - 1$$ Then, we must show that $P(k+1)$ is true   $$ \sum_{i=1}^{k+1} i\cdot i! = ((k+1)+1)! - 1\\ \sum_{i=1}^{k+1} i\cdot i! = (k+2)! - 1$$  I am currently struggling with the next step to show that $P(k)$ is equal to $P(k+1)$. How would I finish this prove by induction? What Is the Difference Between Wizard and Warlock in Potterverse? One of Dumbledore's titles is "Chief Warlock of the Wizengamot".   What is the difference between a Wizard and a Warlock in Potterverse? As we don't see the term Warlock used often in the books, my impression is that a Warlock is somehow officially different from a Wizard.  Please no Wikipedia, HP Wikia, or dictionary.com answers. I'm looking for a canon-based&#185; explanation.  &#185;Any of the ten HP books or a quote from JKR How can I get rid of those little white dots? I am using Blender 2.70a. Let $I = \{a +ib \in \Bbb Z[i] : a$ and $b$ are both multiple of $5\}$. Let $I = \{a +ib \in \Bbb Z[i] : a$ and $b$ are both multiple of $5\}$. Show that $I$ is an ideal of $\Bbb Z[i]$. Is $I$ a maximal ideal? And to find the numbers of elements of the quotient ring $\Bbb Z[i]/ I$.  I have shown that $I$ is an ideal of $\Bbb Z[i]$. But how to verify that $I$ a maximal ideal or not?   And to find the numbers of elements of the quotient ring $\Bbb Z[i]/ I$.   Is there any general way to verify when  $I = \{a +ib \in \Bbb Z[i] : a$ and $b$ are both multiple of $n\}$ will be maximal or not? Is it appropriate to down-vote posts containing SQL injection vulnerabilities? How does Incense work? biblatex broken overnight As late as last week my setup for biblatex worked fine. Going back to the same project today not even a minimal file compiles:  \documentclass{article}   \usepackage{biblatex} %\addbibresource{biblatex-examples.bib}   \begin{document}  test%foo\nocite{*}    %\printbibliography  \end{document}   but breaks off with   /usr/local/texlive/2017/texmf-dist/tex/latex/biblatex/biblatex.sty:3776: LaTeX  Error: Missing \begin{document}.  See the LaTeX manual or LaTeX Companion for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.3776   australian,newzealand} ?  /usr/local/texlive/2017/texmf-dist/tex/latex/biblatex/biblatex.sty:3776: Math f ormula deleted: Insufficient symbol fonts. \expandafter -&gt;american|  l.3776   australian,newzealand}   And keeps repeating the last one until    (That makes 100 errors; please try again.)   when I ignore it.  Files without biblatex work as expected.  Using tlmgr to go my two backup versions of biblatex back in time to 1st Jan I still get the same errors.  Could this be another update from the last week or so that causes this?  If I swich back to TL 16 things work as expected. (For my work I need TL 17 because of packages.) What is the mass density distribution of an electron? I wanted to left align a set of equations. I've tried the solution provided in  . It worked. But, I wanted to have a single equation number for the entire flalign in order to refer to it later. Like in case of equation+split. While using equation+align, I am able to get it. But, if I use equation+flalign the equations are still being centered. Is there a way to do it?  Example using equation+align,  \begin{equation}      \begin{align}       \mbox{Minimize } &amp; x_1+x_2+x_3 \\       \mbox{Subject to} &amp; \\        &amp; x_1+x_2 \leq 10 \\        &amp; x_2+x_3 \leq 8 \\        &amp; x_1+x_3 \leq 5       \end{align} \end{equation}   I would like to do this while the equations are left aligned.  It will be even better if the equations can be spaced a little (for example, 1 cm) from the left margin instead  of starting from the left margin.  Thanks in advance Why not use "which"? What to use then? When looking for the path to an executable or checking what would happen if you enter a command name in a Unix shell, there's a plethora of different utilities (which, type, command, whence, where, whereis, whatis, hash, etc).  We often hear that which should be avoided. Why? What should we use instead? I have a 8 GB pendrive. I used to write raw data into the pendrive (without creating filesystem) using the dd command.    Today, when I inserted the pen drive, the I am unable to write anything on to it.  When I open gparted it is showing the total space on the pen drive as 500 MB. I am unable to create a new partition table or a partition on the pen drive now.   Here is the fdisk -l output.   Disk /dev/sdb: 0 MB, 512000 bytes 255 heads, 63 sectors/track, 0 cylinders, total 1000 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00095df6   What's wrong with the pen drive? How can I recover the lost space?   Device Boot      Start         End      Blocks   Id  System   When I open gnome-disks, it shows the total space as 8 GB but when I try to create a new partition using it, it shows the following error:  Error creating partition on /dev/sdb: Command-line parted --align optimal --script "/dev/sdb" "mkpart primary ext2 1MiB 7969177599b"' exited with non-zero exit status 1: Error: The location 7969177599b is outside of the device /dev/sdb.  (udisks-error-quark, 0) Embedding ordinals in $\mathbb{Q}$ All countable ordinals are embeddable in $\mathbb{Q}$.  For "small" countable ordinals, it is simple to do this explicitly.  $\omega$ is trivial, $\omega+1$ can be e.g. done as $\{\frac{n}{n+1}:n\in \mathbb{N}\} \cup \{1\}$.   $\omega*2$ can be done as $\{\frac{n}{n+1}:n\in \mathbb{N}\} \cup \{1+\frac{n}{n+1}:n\in \mathbb{N}\}$, and $\omega*n$ as $\bigcup_{i\le n} \{i+\frac{n}{n+1}:n\in \mathbb{N}\}$  That immediately also gives $\omega^2$ as  $\bigcup_{i \in \mathbb{N}} \{i+\frac{n}{n+1}:n\in \mathbb{N}\}$  And going further is still relatively easy: We can biject the above embedding of $\omega^2$ onto a single interval $(0,1)$, e.g. through $f(x)=1-\frac{1}{x+1}$ since this is an order preserving bijection from $\mathbb{Q}^+$ to $(0,1)$, allowing us to get $\omega^2+n$, $\omega^2*n$ etc. And by iterating that process, we can get any ordinal below $\omega^\omega$.   But this sort of embedding fails at $\omega^\omega$ as the iteration of $f$ doesn't seem compatible with taking the infinite union - figuratively speaking, we'd squish things to $0$. So what would an explicit embedding of $\omega^\omega$ look like? And the question, then, is if it is possible to give an explicit embedding of $\epsilon_0$? Is the fact that Peano arithmetic cannot prove well-foundedness of $\epsilon_0$ an indication that it cannot be embedded by such elementary functions and their iterations?  And what about even bigger countable ordinals such as the Veblen ordinals, Feferman-Schütte, Bachmann-Howard? From its definition, even if the above all are possible, I assume that the definitive bound of where one can define an effective procedure for the embedding must be Church–Kleene - is that a correct conclusion?  Lastly, does the situation change when we use $\mathbb{R}$ instead of $\mathbb{Q}$, which would allow us to use, perhaps, more easily understood yet inherently complex functions?  Edited because $\omega^2 \neq \omega^\omega$