I am using Ubuntu 19.04 and getting this error.    How to fix this?
When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?
I would like to have my whole document showing a blank line (or space) between paragraphs and no indentation. I know how to do it line by line, but is there a way to change that with just one or a few lines at the beginning of the document? Like a package you can install, or a new command? Is there a nice solution to get a "presenter mode" for Latex presentations? Sufficient condition(s) for $f'$ to be Riemann integrable How to adjust the gap between figure and caption within the same subfloat He has  yet to receive an appointment.   He is yet to receive an appointment.      Is there any difference in meaning? Is one more correct than the other? Haar Measure on Semidirect Product of Unimodular Groups Let $M, N$ be closed subgroups of a given locally compact topological group such that the product $P = MN$ is semidirect, with $M$ normalizing $N$.  Assume second countable, sigma compact, whatever so that Radon products coincide with product measures.  To make life easy, assume $M, N$ are unimodular.  How do we construct a Haar measure on $P$? It seems i'm not gonna find an answer for this question which does not use LHopital's rule. How do you prove limit of (lnx)/x approaches 0 as x moves toward infinity WITHOUT using LHopital's rule? Show that the polynomial $X^5 + X^3 + \bar{1}$ in $(\mathbb{Z}/2\mathbb{Z}[X])$ is irreducible How can I get bash to perform tab-completion for my aliases? I have a bunch of bash completion scripts set up (mostly using bash-it and some manually setup).    I also have a bunch of aliases setup for common tasks like gco for git checkout. Right now I can type git checkout dTab and develop is completed for me but when I type gco dTab it does not complete.    I'm assuming this is because the completion script is completing on git and it fails to see gco.    Is there a way to generically/programmatically get all of my completion scripts to work with my aliases?  Not being able to complete when using the alias kind of defeats the purpose of the alias. To find all $n$ such that $(n-1)!+1$ is a perfect power of $n$ I added a new field on Opportunity table to keep a count of records, as well as track the updates made on that record.  This is needed for an external system we use. Opportinity table already has around 5000 records now. I would like to update the new field that I added with some sequence order initially. Say each record to have a unique sequence number like 1,2,3 etc(can't use the Id field for unique). The field "Identifier__c" was added for this purpose with data type number and unique contraint. For that I created a temporary class and trigger. But it is throwing the error.     Review all error messages below to correct your data. Apex trigger OpportunitySAPIdentifierHandler caused an unexpected exception,   contact your administrator: OpportunitySAPIdentifierHandler: execution   of BeforeUpdate caused by: System.DmlException: Update failed. First   exception on row 0 with id 006E00000038FPSIA2; first error:   CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, OpportunitySAPIdentifierHandler:   execution of BeforeUpdate caused by: System.DmlException: Update   failed. First exception on row 0 with id 006E00000038FPTIA2; first   error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY,   OpportunitySAPIdentifierHandler: execution of BeforeUpdate caused by:   System.DmlException: Update failed. First exception on row 0 with id   006E00000038FPSIA2; first error: SELF_REFERENCE_FROM_TRIGGER, Object   (id = 006E00000038FPS) is currently in trigger   OpportunitySAPIdentifierHandler, therefore it cannot recursively   update itself: [] Class.AutoNumber.OpportunityAutoNumber: line 76,   column 1 Trigger.OpportunitySAPIdentifierHandler: line 4, column 1: []   Class.AutoNumber.OpportunityAutoNumber: line 76, column 1   Trigger.OpportunitySAPIdentifierHandler: line 4, column 1: []:   Class.AutoNumber.OpportunityAutoNumber: line 76, column 1   Below is the trigger and class used.  trigger Opportuniwith sIdentifierHandler on Opportunity (before insert,before update) {          If(Trigger.isInsert || Trigger.isUpdate){             AutoNumber.OpportunityAutoNumber(Trigger.new);         }   }   The class is   public with sharing class AutoNumber {       public static void OpportunityAutoNumber (List&lt;Opportunity&gt; Opp) {          if(Trigger.isUpdate || Trigger.isInsert) {              for(Opportunity p: Opp) {                  List&lt;Opportunity&gt; oppList = new List&lt;Opportunity&gt;();                 oppList = [SELECT Id, createdDate, Identifier__c FROM Opportunity where Identifier__c = null and Id != :p.Id limit 100 FOR update];                 for (Opportunity oppL: oppList) {                      if(oppL.Identifier__c == null) {                          List&lt;Opportunity&gt; OpportunityList = new List&lt;Opportunity&gt;([select Identifier__c from Opportunity where Identifier__c != null order by Identifier__c desc limit 1]);                          if (!OpportunityList.isEmpty()) {                               Decimal maxval = OpportunityList.get(0).Identifier__c;                             oppL.Identifier__c = maxval + 1;                             update oppL;                         }                      }                     // integer currentCounter = Integer.valueOf(opp.Identifier__c);                     // oppr.Identifier__c = currentCounter + 1;                     // update oppr;                 }             }         }        }  } What is the difference between ++i and i++? Integer solutions to combinations of floating point numbers Imagine two kids each sitting in the center of their own tilt-a whirl®, each holding steady a flashlight (or laser) whose beam is parallel to the deck.  Each machine rotates and precesses (we'll leave out nutation) at different, real, rates.  How do we determine the least number of rotations to alignment, for each kid. If you prefer another analogy: Saturn and Jupiter orbit with different (real) periods.  How many orbits for each until conjunction in precisely the same position in space?  Simplify by assuming circular, observer-centric, orbits. specifically solutions to: aC1 + bC2 = N where a, b, N are positive integers of your own choosing and C1, C2 are constant, unique, positive, non-integer(real) numbers where C1 &lt; C2. I am hoping to avoid rigorous computational methods involving modulus tests. Hope I clarified the ambiguities. Thanks, @DonThousand the Bezout identity looks interesting. I need to upgrade my existing Ubuntu system, and I also want to install Ubuntu on a new laptop.  I would like to have an installation CD or DVD to do both of these.  Where exactly I can order or request an Ubuntu installation CD/DVD/USB? What is a magic number, and why is it bad? In Java, what is the best way to determine the size of an object? Custom post type - posts list - white screen of death i am getting a weird error - white screen in the list of posts for a specific Custom post type (just for that one)   tried deactivating all the plugins tried checking for error (debugging = true)   Still nothing the page just doesnt echos anything... (nothing in source too)  I am talking about such a url in the admin:     Here is register_post_type part i am using:    function register_submodelcpt() {     $labels = array(         'name'                  =&gt; __('Sub Models', THEME_NAME),         'singular_name'         =&gt; __('Sub Models', THEME_NAME),         'add_new'               =&gt; __('New Model', THEME_NAME),         'add_new_item'          =&gt; __('Add new Model', THEME_NAME),         'edit_item'             =&gt; __('Edit Model', THEME_NAME),         'new_item'              =&gt; __('New Model', THEME_NAME),         'all_items'             =&gt; __('All Sub Models', THEME_NAME),         'view_item'             =&gt; __('Watch Model', THEME_NAME),         'search_items'          =&gt; __('Search Models', THEME_NAME),         'not_found'             =&gt;  __('No Models found', THEME_NAME),         'not_found_in_trash'    =&gt; __('No Models found in trash', THEME_NAME),          'parent_item_colon'     =&gt; '',         'menu_name'             =&gt; __('Sub Models', THEME_NAME),      );      $args = array(         'labels'                =&gt; $labels,         'public'                =&gt; true,         'publicly_queryable'    =&gt; true,         'show_ui'               =&gt; true,          'show_in_menu'          =&gt; true,          'query_var'             =&gt; true,         'rewrite'               =&gt; array('slug' =&gt; 'submodels'),         'capability_type'       =&gt; 'post',         'has_archive'           =&gt; true,          'hierarchical'          =&gt; true,         'menu_position'         =&gt; 5,         'menu_icon'             =&gt; get_stylesheet_directory_uri().'/images/cpt/subcars.png',                     'supports'              =&gt; array('title', 'thumbnail', 'revisions', 'page-attributes')     );      register_post_type('submodelscpt',$args); } add_action('init', 'register_submodelcpt');   Did anyone encounter such an issuse? can you think of a reason this might happen?   Another weird thing when i change this:    To this:     The posts list loads correctly... Is $f(a)\!=\!0\!=\!f(b)\Rightarrow (x\!-\!a)(x\!-\!b)\mid f(x)\,$ true if $\,a=b?\ $ [Double Factor Theorem] I lost the sa password on a machine, and when I log in to the machine directly using an account in the admin group, SQL Server Management Studio will not allow me to log in using Windows authentication.  My plan was to simply log into the server, connect via Windows Authentication, and reset sa to use a new password. Since I cant' connect via Windows Authentication, this won't work.  How else can I reset the sa password? Imagine you're trapped inside a free falling elevator. Would you decrease your impact impulse by jumping during the fall? When?