I've been trying to run sudo apt update and I get this output that doesn't seem to actually update: Hit:1 https://repo.steampowered.com/steam stable InRelease  Hit:2 http://dl.google.com/linux/chrome/deb stable InRelease                 Hit:3 http://packages.microsoft.com/repos/vscode stable InRelease            Get:4 http://kali.download/kali kali-rolling InRelease [30.5 kB]          Err:4 http://kali.download/kali kali-rolling InRelease   The following signatures couldn't be verified because the public key is not available: NO_PUBKEY ED444FF07D8D0BF6 Reading package lists... Done W: GPG error: http://kali.download/kali kali-rolling InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY ED444FF07D8D0BF6 E: The repository 'http://http.kali.org/kali kali-rolling InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  It doesn't seem to actually update (unless it is and I just can't see it), and I don't know what's causing the issue. I'm running Ubuntu 20.04.1 LTS with AMD64 build. Does anyone have a possible theory to what this is, or even a fix?
I added some extra repositories with the Software Sources program. But when I reload the package database, I get an error like the following:     W: GPG error:  trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F   I know I can fix it using apt-key in a terminal, according to the official Ubuntu documentation. But I would have liked to do it graphically. Is there a way to do this without using a terminal?
How to "freeze" a cloth animation at X frame? How would one freeze a simulated body at frame X and use it as a static mesh?  Following a , I've been able to do a cloth animation to my model, now I'd like to have that made static, without the use of the timeline.   The thing is, I'm modelling something that's not going to be an animation, but a static object (something like a statue/figurine). So I don't need the animation, only the shape at a particular frame that I find convenient. I'd like eventually once this is done, to also modify that deformed grid.   I've tried to follow what was said , but couldn't figure out what chipmasque was saying. I'm quite new to blender (been using it on and off, just enough to forget everything).  I'm using blender 2.63, if it is of any relevance. How can I edit this trigger to only fire once? I would like to create a half-turn staircase without a landing. Is there an easy way to accomplish this without having to manually calculate and create each step individually?  Here’s an image similar to what I would like to achive:    I have found the Archimesh add-on including . While I can bend the created stairs, I haven’t found any way to get anywhere close to the image above. My stairs just always look out of shape and I don’t know how to get the outline of the staircase into a square.  I should mention that I only have very little experience with Blender modeling, so it’s well possible that I’m just missing some curve modification basics. Perhaps Archimesh is also the wrong approach for this in the first place? $\operatorname{Hom}(X \times Z, Y) \cong \operatorname{Hom}(X, \operatorname{Map}(Z, Y))$ is not true in $\textbf{Top}$ I read that in the category of topological space it is not true that $\operatorname{Hom}(X \times Z, Y) \cong \operatorname{Hom}(X, \operatorname{Map}(Z, Y))$ for every $X, Y, Z$ topological spaces. In particular, I read that this does not work when $Z = \mathbb{R} \setminus \{ 1/n \mid n \in \mathbb{N}\}$. This was not explained, i.e. there was no example.   I am looking for an example or – maybe better – just a hint.  EDIT   $\operatorname{Map}(Z, Y)$ is endowed with the compact-open topology $\cong$ means just bijection; i.e. there is already an obvious bijection as sets, but the claim is that (I think) sometimes the "output function" is not continuous Web colors: how to compensate for differences in monitors I have gotten as far as to create the bootable usb, booting into that bootable usb and getting to the install options however i quit because I had some concerns.  I currently have a Samsung 850 evo 1tb that has win 10ninstalled. I want to dual boot with Ubuntu 18.04 by installing it on a brand new unformatted uninitialized Samsung 860bevo 250gb. Should i format the brand new ssd as a new volume in win 10 and then proceed with the Ubuntu install on this volume. What else should i do? Im a first time Ubuntu user and installer.  Any and all help is appreciated. Microsoft Excel mangles Diacritics in .csv files? Can all fundamental forces be fictitious forces? Avoiding Error 1325 EsriPyFldr not valid short file name when uninstalling ArcGIS for Desktop? I am trying to uninstall ArcGIS 10.3.1 for Desktop from Windows 7 SP1 using Uninstall a program and I am receiving an error message (pictured below):     Error 1325. EsriPyFldr is not a valid short file name.   The error message dialog appears just after:     Computing space requirements   seems to complete.  If anyone else has encountered this, then have you been able to find a way to get past it and uninstall ArcGIS 10.3.1 for Desktop?  My machine has what I would call a vanilla install of ArcGIS 10.3.1 for Desktop and ArcGIS Pro 1.1.1 so there are Python versions 2.7.8 and 3.4.1 as a result. ArcGIS Earth Beta is also on the machine.     I have made a posting on the same issue to   After running this utility () unsuccessfully (it hung for two hours before I killed it) the error message when trying to uninstall shifted to:     This action is only valid for products that are currently installed     ArcMap 10.3.1 continues to start fine and doing  wmic product where "Vendor like '%Environmental Systems Research Institute%'" get Name, Version, InstallDate, InstallLocation in a DOS window (at the suggestion of @MattWilkie) reports only the presence of Python 3.4.1 for ArcGIS Pro, ArcGIS Pro and ArcGIS Earth on my machine. How does iCloud Photo Library's "Optimize iPhone Storage" setting work in relation to other photo apps on iOS? If I have Optimize iPhone Storage enabled on my iPhone and my phone storage is completely full, I understand that iOS will only store a low-res thumbnail of many of my photos on the device. (The full high-res version of the image will only exist in iCloud and on devices with Download and Keep Originals enabled.)  But when only thumbnails exist on the device, how does that work in relation to other photo apps on iOS? For example, do third-party cloud-based photo apps (like Google Photos, Dropbox's Carousel, or Amazon Prime Photos) have access to the full high-res images from the iCloud Photo Library? Or will they only see the low-res thumbnails in some cases? How to install the most common plugins? Can I add jars to Maven 2 build classpath without installing them? Maven 2 is driving me crazy during the experimentation / quick and dirty mock-up phase of development. I have a pom.xml file that defines the dependencies for the web-app framework I want to use, and I can quickly generate starter projects from that file. However, sometimes I want to link to a 3rd party library that doesn't already have a pom.xml file defined, so rather than create the pom.xml file for the 3rd party lib by hand and install it, and add the dependency to my pom.xml, I would just like to tell Maven: &quot;In addition to my defined dependencies, include any jars that are in /lib too.&quot; It seems like this ought to be simple, but if it is, I am missing something. Any pointers on how to do this are greatly appreciated. Short of that, if there is a simple way to point maven to a /lib directory and easily create a pom.xml with all the enclosed jars mapped to a single dependency which I could then name / install and link to in one fell swoop would also suffice. I am developing an application and can not figure out a proper abstract term that would fit an interface that defines an object as Movable and Resizable (In essence, something that has a defined size and defined position). Calling it Movable and resizable is kind of silly. Layout was a term that came to my mind but it is not good as layout is something that is responsible for defining position and size, not containing it. Thanks a lot. What are Java command line options to set to allow JVM to be remotely debugged? Number of elements in the quotient ring $\mathbb{Z}[X]/(X^2-3, 2X+4)$ Does $x^2 - y^2 = 12345678$ (x,y are integers) have any solutions? I am trying to prove the following statement but have trouble  comprehending/going forward with some parts! Here is the statement:     If $A$ is any set, then  $|A|$ $&lt;$ $|P(A)|$   Here is what I have so far:  We need to show that there is an injection from $A$ to $P(A)$ but not a surjection.   A natural choice for an injection is the function $ f(x)$ $=$ $\{x \}$, which in plain English, takes any element $x$ (that is in $A$) and sends it to the one-element set $\{x \}$. Thus $f(x)$ is injective!  To show that there is no surjection, for the sake of contradiction, assume there is a surjection. Here is where I start to have trouble. Surjectivity means that every element of the co-domain is mapped to an element of the domain, correct? Consequently, in this particular case, we are "matching" sets (from $P(A)$) to elements (from $A$) right?  If the above is correct, my problem arises here. I am not sure how to prove that $f$ is not surjective. Unfortunately, I am easily confused by notation so please explain in English.  Thank you in advance!! :) Every proper ideal is contained in a maximal ideal, in a commutative ring with identity. The statement is:     In a commutative ring with 1, every proper ideal is contained in a maximal ideal.   and we prove it using Zorn's lemma, that is, $I$ is an ideal, $P=\{I\subset  A\mid A\text{ is an ideal}\} $, then by set inclusion, every totally ordered subset has a bound, then $P$ has a maximal element $M$.  My question is why $M$ must contain $I$? When can I say that $\cup H_i$ is a group? Let $G$ be a group and $\{H_i\}_{i\in I}$ a family of subgroups. I would like to find a condition that will imply that $\cup_{i\in I} H_i$ is a subgroup. I know that it's not true in general, I need help to find this condition.  Any help is welcome.  Thanks a lot. How do I prevent and/or handle a StackOverflowException? I would like to either prevent or handle a StackOverflowException that I am getting from a call to the XslCompiledTransform.Transform method within an Xsl Editor I am writing. The problem seems to be that the user can write an Xsl script that is infinitely recursive, and it just blows up on the call to the Transform method.  (That is, the problem is not just the typical programmatic error, which is usually the cause of such an exception.)  Is there a way to detect and/or limit how many recursions are allowed?  Or any other ideas to keep this code from just blowing up on me?