In a sentence "What's up, my friends?" and "Hey, everyone!" should I put a comma between "What's up" and "friends" and "Hey" and "everyone" respectively? Is there a particular set of rules?
According to some grammars[1][2] and CMS...  "Interjections and vocative should be separated from the rest of the sentence by commas".  The vocative case [1] is used to indicate direct address (i.e., to show when you are talking to somebody or something directly). Nouns in the vocative case are set off using commas. CMS 6.38  As direct address (i.e. vocative case), the parenthetical element should be set off using commas (CMS 6.30). An absolute phrase is always treated as a parenthetical element, as is an interjection.  So,      Hello, world!   That is a very classical way to hello the world.  But, languages change. I am not sure, but today, I feel that it is very uncommon helloing someone with an interjection, providing a small pause and clarifying who is helloed. I have an impression that usually people use hello as a ("kind of") verb, not an interjection.   Question: Is that just a personal (bad) impression or some linguistic has already studied that phenomenon?     [1] - Nelson, Gerald C., Director Survey of English Usage Sidney Greenbaum, and Sidney Greenbaum. An Introduction to English Grammar. Routledge, 2013. [2] - Advanced Grammar in Use with Answers: A Self-Study Reference and Practice Book for Advanced Learners of English. 3 edition. Cambridge University Press, 2013. CMS - Chicago Manual of Style
Obviously, this suggested edit should never have been approved. Because it's very, very minor.  Is it acceptable for me to "rollback" this edit? Does the suggested editor lose the +2 rep when I roll it back? Should I comment on one of his questions, explaining not to make too minor edits like this?  Is there anything I should do to notify the reviewers that approved  too minor suggested edit? C++ GCC 4.3.2 error on vector of char-array Prove that ${x dy - y d x\over x^2 + y^2}$ is not exact Is there a formal proof for the superposition theorem? Careers: What does "allows remote" mean? When a posting is marked "allows remote", does it mean work in the office some days, work from home some days?  Or does it mean you could actually live out of town and maybe fly in as needed?  The reason I ask is I'm really interested in public facing software rather than internal/enterprise stuff, and most of that seems to happen in a few very expensive cities.  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System.ListException: Before Insert or Upsert list must not have two identically equal elements - Deep Dive I had the following exception thrown at me when trying to process more than one selected records via a custom button in the list view.    Class Code  global class MerchandiseInventoryClass {      webservice static void ConverttoInventory(String[] merchandise_id)    {        //Convert Merchandise collection into Inventory Collection...         Merchandise__c[] merchandise_collection = [SELECT ID,Author__c,Book_Title__c,Edition__c,Publisher__c,Total_Merchandise_QtyTotal_Qty__c,Status__c FROM Merchandise__c WHERE ID = :merchandise_id];          Inventory__c i = new Inventory__c(); //Line 1        List&lt;Inventory__c&gt; newInventory = new List&lt;Inventory__c&gt;();        for(Merchandise__c m : merchandise_collection )        {            if(m.Status__c !='Fully Converted')            {            i.Author__c = m.Author__c ;            i.Book_Title__c = m.Book_Title__c;            i.Edition__c = m.Edition__c;            i.Publisher__c = m.Publisher__c;            i.Qty_Available__c = m.Total_Merchandise_QtyTotal_Qty__c;            i.Merchandise__c = m.Id;            m.Uninventoried_Qty__c = 0;            m.Status__c = 'Fully Converted';            newInventory.add(i);            }        }        insert newInventory;        update merchandise_collection;    }  }   By moving the Line 1 to within the for loop solved the issue for me.  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I would like to upgrade a Toshiba Satellite C55-A5300 laptop so it can be as useful as it can be nowadays. I haven’t needed to use much software for a few years now, and I’m not able to gauge whether a maxed out upgrade of this laptop would be up to running the latest versions of MS Office and Acrobat smoothly. Maybe even run some Photoshop and Lightroom? I want to install the best CPU that will work optimally within the parameters of this laptop, including the laptop’s cooling capabilities. I ultimately want improved performance, but I want the performance to be as smooth as possible. From what I gather the Pentium 2030M is the best processor this motherboard will accept. Am I on the right track? I also plan to fully upgrade the memory and the hard disk speed with respective upgrades. What is the max memory per RAM slot (2 total)? What is the fastest speed of RAM I can use?  Copied from the Toshiba spec sheet:  Processor and Graphics Intel® Celeron® Processor 1037U o (2M Cache, 1.80GHz) Mobile Intel® NM70 Express Chipset Mobile Intel® HD graphics with shared graphics memory Memory Memory Configured with 4GB DDR3 1333MHz (max 16GB) 2 main memory slots. One slot is occupied Storage Drive 500GB (5400 RPM) Serial ATA hard disk drive Power 45W (19V 2.37A) 100-240V/50-60Hz AC Adapter Proving an identity for Bernoulli polynomials Consider the Bernoulli polynomials $B_n(x)$ given by the expansion  $$\frac{te^{xt}}{e^t-1} = \sum\limits_{n=0}^{\infty}B_n(x)\frac{t^n}{n!}.$$  I want to prove the identity $$B_n(1-x)=(-1)^nB_n(x).$$  This formula is given in a lot of books, but unfortunately without any proof. Therefore I'm wondering how to prove it. Do you have any idea?  I tried for instance:  $\sum\limits_{n=0}^{\infty}B_n(1-x)\frac{t^n}{n!}=\frac{te^{-xt}}{e^t-1}e^t=\left(\sum\limits_{n=0}^{\infty}B_n(-x)\frac{t^n}{n!}\right)\sum\limits_{n=0}^{\infty}\frac{t^n}{n!}=\sum\limits_{n=0}^{\infty}\left(\sum\limits_{l=0}^n\binom{n}{l}B_{l}(-x)  \right)\frac{t^n}{n!}$.  Hence  $B_n(1-x)=\sum\limits_{l=0}^n\binom{n}{l}B_{l}(-x)$.  But I do not know how to proceed.  On the other hand I know that $B_n(x+1)-B_n(x)=n x^{n-1}$. Hence  $B_{n}(1-x)=B_{n}(-x)-n(-x)^{n-1}$. But again, I do not know how I can go further.   Hopefully someone can help me.  Best regards