I've been searching this site and googling everywhere and can't find an answer so chances are that I'm out of luck and not possible to do...  Anyway, I'm working on a old site that adds elements with IDs. Those elements can be present more than one on the same page... and yes, I know that is bad practice, but that is the way I got it and can't change it so I have to work with I have.  So my question is if it's possible to add a number to the ID in the html page, that I can access, to make it so that those IDs be something like name_123, being that the number would change for every new element added into the page?  I suposse I can change the IDs to class but I would still need a way to have an unique identifier...  Any help pointing me in the right direction? Or any other sugestion?  Thank you.
When creating the id attributes for HTML elements, what rules are there for the value?
ref to subsection number only It is easy to find the minimum of $\|Ax-b\|_2$, when $A$ has full column rank. But how is the case when we add the constraint $\|x\|_2=1$? Or, to be explicit,  $$\min_{\|x\|_2=1}\|Ax-b\|_2=?$$  My idea is to construct the corresponding Lagrange function  $$L(x,\lambda) = (Ax-b)^T(Ax-b) + \lambda(x^T x - 1)$$  Differentiate the function with respect to $x,\lambda$, we have  $$A^T A x - A^T b + \lambda x = 0$$  $$x^T x=1$$  However, I find it hard to move forward to get the answer. Could anyone help me? Thanks a lot! The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this? What are the strategies for getting feedback on articles? As an academic, one has to publish. Often, an article is drafted, and you need feedback of a colleague.  I see that quite often some perspective articles are often written by long-term collaborating pairs of authors.  What are some strategies people use to get feedback on their articles  (outside of immediate boss; and in the case that none of the friends in the field of work in the specific domain of the article, and one needs specific (not general) feedback)?   How do you approach a colleague to simply read your article. Or do you just mention it at a conference to the most suitable colleague - would you like to read an article and give me feedback? How do handle the co-authorship or acknowledgement? Do you establish the limits at the "approach time"?  What are some strategies to establish a "publishing" duos (buddies). Hibernate JPA Sequence (non-Id) Is it possible to use a DB sequence for some column that is not the identifier/is not part of a composite identifier?   I'm using hibernate as jpa provider, and I have a table that has some columns that are generated values (using a sequence), although they are not part of the identifier.  What I want is to use a sequence to create a new value for an entity, where the column for the sequence is NOT (part of) the primary key:  @Entity @Table(name = "MyTable") public class MyEntity {      //...     @Id //... etc     public Long getId() {         return id;     }     //note NO @Id here! but this doesn't work...     @GeneratedValue(strategy = GenerationType.AUTO, generator = "myGen")     @SequenceGenerator(name = "myGen", sequenceName = "MY_SEQUENCE")     @Column(name = "SEQ_VAL", unique = false, nullable = false, insertable = true, updatable = true)     public Long getMySequencedValue(){       return myVal;     }  }   Then when I do this:  em.persist(new MyEntity());   the id will be generated, but the mySequenceVal property will be also generated by my JPA provider.  Just to make things clear: I want Hibernate to generate the value for the mySequencedValue property. I know Hibernate can handle database-generated values, but I don't want to use a trigger or any other thing other than Hibernate itself to generate the value for my property. If Hibernate can generate values for primary keys, why can't it generate for a simple property? After a very long time will we see more stars (due to the fact that more light is get to us) or less stars (as the universe expends and light have to pass larger distance)? In general, can stellar objects go outside of the scope of the observable universe or is it only growing with time? Calculations are always better than just discussion. Does it have any connection to dark matter? Is it true or false that $\lvert P([0, 1]) \setminus P((0, 1)) \rvert > \lvert P(\mathbb{N}) \rvert$ Is it true or false that $\lvert P([0, 1]) \setminus P((0, 1)) \rvert &gt; \lvert P(\mathbb{N}) \rvert$ ?  I need a hint because I don't see a way to solve this I'm new to LaTeX and I'm trying to figure out how to correctly format a proof. Can someone show me a basic template for how to do this?   The part I am having the most trouble with is creating new columns and customizing alignment... for instance, how do I add a right-aligned annotation (i.e. by distributive property) to a line of this sample proof? Should I use eqnarray* or is there a better option?  \begin{proof}   Let $t,u \in \mathbb{R}$ where $t=xy$ and $u=zw$. So,   \begin{eqnarray*}     4xyzw &amp;=&amp; 2\cdot2tu \\     &amp;\le&amp; 2\cdot(t^2+u^2) \\     &amp;=&amp; 2\cdot((xy)^2+(zw)^2) \\     &amp;=&amp; 2\cdot(x^2y^2+z^2w^2) \\     &amp;=&amp; 2x^2y^2+2z^2w^2 \\     &amp;\le&amp; ((x^2)^2+(y^2)^2)+((z^2)^2)+(w^2)^2) \\     &amp;=&amp; x^4+y^4+z^4+w^4   \end{eqnarray*} \end{proof} Short-cut for switching to a given directory In the Ubuntu terminal I find myself spending considerable time to switch to a particular directory every time the computer starts up. Is there some way I can make this process easier? Is there some hotkey or some quick directory change that I can use (like speed dial on a phone)?   eg:     cd 1:Changes to saved directory one Why does a bigger sensor lead to a shallower depth of field? Proving inequality $(a+\frac{1}{a})^2 + (b+\frac{1}{b})^2 \geq \frac{25}{2}$ for $a+b=1$ If $a, b$ are positive real numbers and $a+b = 1$, prove that :  $$\left(a+\frac{1}{a}\right)^2 + \left(b+\frac{1}{b}\right)^2 \geq \frac{25}{2}$$  I can see that the value $\frac{25}2$ is attained for $a=b=\frac12$. But I do not know how to show that this is the minimal possible value.  Thank you. Your visa application has been concluded - what does this mean? I got two mails from the UK embassy in Abu, saying your visa application has been concluded. I'm really confused, did I get the visa or not? What could the possible results be? In high Reynolds numbers we have turbulent flow. This is because the inertial forces are much greater than the viscous forces. I understand inertial forces to be actually the fictional forces due to the momentum of the moving fluid. And viscous to be the forces that drag each layers together. But why when inertial forces are too high than the viscous forces, there is turbulence? Why don't the molecules just continue to move laminarly due to their momentum? I can assume the viscous forces are not very strong in high speeds (in high inertial forces) to keep them together to form a laminar flow? But again, why they result in irrational movement after the effect of viscous forces is not anymore considerable? As a mechanical analogue, if I have balls attached together and make them travel linearly, and remove their between them attachment, they can continue to travel linearly. But what happens in fluid molecules that turbulence is created? How to get a list of current open windows/process with Java? Does any one know how do I get the current open windows or process of a local machine using Java?    What I'm trying to do is: list the current open task, windows or process open, like in  Windows Taskmanager, but using a multi-platform approach - using only Java if it's possible. Word for a smart and stubborn person? I'm trying to find a single adjective that would fit the best to the following person's trait:     One who thinks knows everything/best, and often doesn't listen to orders and instead completes some task his/her own way.    This person, while intelligent, is right about 50% of the time, when doing things its own way.   So far I've thought of independent, idiosyncratic and stubborn, but these words don't imply the "knows everything/best" part of the trait. Using QGIS 3 graphical modeler I created a model with a variety of input parameters (> 10). When starting the model, a nice user interface is generated. But the arrangement of the GUI elements is totally confused and apparently unpredictable during creating the model. It does neither seem to depend on the arrangement of input parameters in the graphical modeler nor on the chronological order in which the input parameters are added to the model.   Is there a way that let's me arrange the GUI elements in the order I desire? Pre & post increment operator behavior in C, C++, Java, & C# Proving Cauchy condensation test I was just testing Eevee and found that you cannot view a glass object through another glass. Is there any workaround? It works fine only If I rotate the glass window or put my camera to the back side of the scene Duplicates of an outdated question If a new question addresses the same issue that another question does, but the answers to the original question is sufficiently outdated, should the new question still be closed as a duplicate?