explain xkcd - User contributions [en]

Talk:2304: Preprint

2020-05-14T16:39:35Z

141.101.77.236: Added another possibility to sarcastically pronounce circled (R) sign.

I was going to mention the TeX format(/family), but someone got in there before me. So how about if it's a .wp4 document? ;) [[Special:Contributions/141.101.107.84|141.101.107.84]] 01:40, 9 May 2020 (UTC)
:But now [https://www.explainxkcd.com/wiki/index.php?title=2304:_Preprint&diff=191780&oldid=191776 the LaTeX reference is removed], anyway. [[Special:Contributions/162.158.158.163|162.158.158.163]] 16:14, 9 May 2020 (UTC)

Why is this comic labeled as a Saturday comic? I don't know what timezone you use, but it was posted Friday, well before midnight UTC. [[Special:Contributions/172.69.69.204|172.69.69.204]] 02:15, 9 May 2020 (UTC)

: I'm pretty sure that's just an error. The date for the comic in the [https://xkcd.com/archive/ archive] is "2020-5-8", which is today (Friday). Comic #[[2303]] correctly has the "Wednesday comic" category, and the archive lists its date as 2020-5-6 (which is Wednesday). ...And I've fixed it now. The category is automatically generated based on the date listed in the [[Template:Comic]] infobox at the top of the article; someone incorrectly entered it as "May 9, 2020" instead of "May 8, 2020". --[[User:V2Blast|V2Blast]] ([[User talk:V2Blast|talk]]) 02:53, 9 May 2020 (UTC)
::'Someone' == DgbrtBOT; and thus probably based off the time() it thinks it is, upon autocreating the base article, rather than any human erring. Depending on the home system's timezone, it probably ''was'' Saturday for DB, if not for Randall. Maybe an offset/correction/relocali(s|z)ation should be put into the code, but it seems to normally work out Ok and this comic might have been ''just'' over a threshhold... ''(edit: Wiki time in history seems to be UTC, for me at least - I'm in UTC+1/BST but as an IP-editor I haven't made any setting changes to my personal login that I don't have. DgbrtBOT piped up at 22:48, which at UTC+2 or more (Central Europe Daylight Savings, which matches what I recall of knowing about that entity, or anywhere more Easterly) would have been 'tomorrow', and I didn't spot the new comic until at least those dozen minutes after that which occured before my own clocks ticked past midnight. Given that Randall is (usually?) In UTC-5, or UTC-4 when daylight savings is established, maybe Dgbrt needs a special offset of -6 hours (or go directly via localtime() with the best current known Munroevian locale specified) in calculating things. Or we can let the community smooth these things out like we just did when a possible late-evening update causes this to be an issue?)'' [[Special:Contributions/162.158.155.62|162.158.155.62]] 03:17, 9 May 2020 (UTC)

Is "sarcastically pronouncing the registered trademark symbol" meant as pronouncing it "arr" in the way pirates talk? [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 15:00, 9 May 2020 (UTC)
:I would expect professional news anchors can come with something even more sarcastic. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 01:08, 10 May 2020 (UTC)
::Perhaps they'd go with something like "R in a circle" or "Circled R" (pronounced "Circledar"). [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 17:27, 10 May 2020 (UTC)
::: Perhaps we can use a little of both and create a new [[927:_Standards|standard]] for sarcastically pronouncing it as "circled, arrr!" [[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]]) 12:05, 11 May 2020 (UTC)
:::: ReGiStErEd TrAdEmArK! [[Special:Contributions/108.162.216.128|108.162.216.128]] 20:34, 11 May 2020 (UTC)
: I thought it was meant to be read as "Ado-bear" - but then again, English is not my first language:)

In 2020 I use pdf to put documents with tables onto a website, because html exports from editors are voluminous and brittle. [[Special:Contributions/162.158.6.118|162.158.6.118]] 10:32, 10 May 2020 (UTC)
:As someone who regularly takes tables ''from'' PDF in order to put them into spreadsheets for further use, some people don't do me any favours by that method. Among the problems, if the table setter didn't pay attention to the column widths then the copied-out text of two adjacent cells that don't ''appear'' to overlap each other will interlace at a character level and need editing back to separate entites. And then there's the inconsistencies of Header rows atop the table and/or atop the next newpage the table splits over. I could run a quick script on (X)HTML tables, and get it perfectly for my needs. CSV, or even TabSV, would actually be my preferred transport format (i.e. ''no'' format, just pure layout without even spanned/merged cells, and I can redo what needs redoing on the final redo), but I can't ever seem to get them to do that for me despite having the data almost in that form prior to the PDFing... Grrrr. [[Special:Contributions/162.158.159.142|162.158.159.142]] 11:30, 10 May 2020 (UTC)
:: I feel your pain. I receive pdf documents from a financial professional, where an A4 landscape page seems to have about five two-column-wide tables side-by-side, and I'm still deciding what kind of manipulation to do, to get it into CSV and do some analysis. [[Special:Contributions/162.158.6.232|162.158.6.232]] 10:21, 12 May 2020 (UTC)
::: ''If'' the PDFing hasn't ruined the groupings/precedence, like it often does, try mouse-selecting each table, to copy and paste into notepad or equivalent. Sometimes that works well enough to create tab delimited elements (other times, it line-feeds between columns as well as rows, but still can be reconstructed) and then that'll paste into a spreadsheet (or be parsable with a script) better than any Paste Special (using "no textformat" options?) straight into a grid. Sometimes you need to fiddle a bit with the notepad text, but depending on the data that might be doable with a few choice find+replace runs, perhaps upon consecutive table-pastings to save you time repeating yourself. Or not. [[Special:Contributions/162.158.158.163|162.158.158.163]] 00:08, 13 May 2020 (UTC)

I think Randall's last point (no unprofessional humans use PDFs in 2020) is very wrong. Especially due to the coronavirus, all college classes have switched to online assignment submissions, and the teachers only accept PDF submissions (although, annoyingly, they give the original template files in .doc format!) I would NOT trust random college student's assignment submissions as a reputable information source! [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 17:22, 10 May 2020 (UTC)

Talk:2092: Consensus New Year

2019-01-01T16:58:18Z

141.101.77.236: orthodox new year

Sorry for the server downtime, it should be fixed now. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 17:24, 31 December 2018 (UTC)

: So what was it? Hardware issue, failed software update, reconfiguration boo-boo, external attack, frozen process, Y2K+19 bug? [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 18:30, 31 December 2018 (UTC)
::To be honest: I don't know. But probably a mixture of "external attack" and "frozen process" AND my laziness to check the health of the Wiki by 24/7. I figured it out when the BOT couldn't do the proper updates and some refreshing restarts to some processes did the job. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:54, 31 December 2018 (UTC)

The leftmost label says "10:00 AM EST", but I'm 95% sure that it should be "5:00 AM EST". That makes sense both in terms of time zones / date lines, and also in terms of the number of hash marks (the 9th hash mark before 1:30 PM: 2 PM - 9 = 5 AM). --Brandon [[Special:Contributions/172.69.22.224|172.69.22.224]] 19:35, 31 December 2018 (UTC)
:Agreed. The minor scale tick marks appear to be at 1 hr increments past the "1:30 PM" denoted time. However that doesn't follow for before 1:00 pm to reach the labeled "10:00 AM" mark. [[Special:Contributions/172.68.34.88|172.68.34.88]] 20:59, 31 December 2018 (UTC)
:I suspect he failed to translate the label correctly to EST, since it would be 10:00 AM UST. I'm going to add some content into the explanation on the word "Consensus" from Wiktionary. It has multiple definitions that include both "agreement among the members of a given group" as in a common time to celebrate the New Year, as well as "Average projected value" that might also be applicable here. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 22:35, 31 December 2018 (UTC)
:I'm watching the xkcd page to see if Randall updates the comic image to correct this error. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 00:50, 1 January 2019 (UTC)

I'm actually not certain Randall '''suggests''' a time for universal celebration of New Year. Apart from the word "Consensus", there's nothing to suggest it. Rather, I read it as a stated time where a majority will agree to the statement that it's now 2019. [[Special:Contributions/141.101.96.187|141.101.96.187]] 22:38, 31 December 2018 (UTC)Wilhelm
: I agree that he's probably not suggesting everyone should celebrate at some common time - see my recent edit on the meaning of consensus in the explanation. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 23:27, 31 December 2018 (UTC)

'''Happy NEW YEAR!!!'''

While Randall has to wait... in central Europe it just happened when I'm posting this. And in Germany we don't have only the "Autobahn" with no speed limit, every eighteen year old or older child plays with fireworks...

Nonetheless not only in California there are some people giving more attention to a much more unique event: New Horizons is passing {{w|(486958) 2014 MU69|Ultima Thule}}, six ''light hours'' away from Earth.
Let's see if Randall does cover this event. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 23:49, 31 December 2018 (UTC)

On the topic of Orthodox churches using shifted Julian calendar: I can't speak for the entire world, but here in Russia it's not really relevant, since the church calendar is limited to religious matters, and New Year is a secular holiday. (But Orthodox Christmas will in fact be observed on Jan 7th.) There ''is'' an obscure holiday called Old New Year that is New Year shifted to 14th, but hardly anyone celebrates it and it certainly doesn't replace the regular one. [[Special:Contributions/141.101.77.236|141.101.77.236]] 16:58, 1 January 2019 (UTC)

2028: Complex Numbers

2018-12-20T20:13:46Z

141.101.77.236: /* Explanation */ Fix typo and add missing word

{{comic
| number = 2028
| date = August 3, 2018
| title = Complex Numbers
| image = complex_numbers.png
| titletext = I'm trying to prove that mathematics forms a meta-abelian group, which would finally confirm my suspicions that algebreic geometry and geometric algebra are the same thing.
}}

==Explanation==
The {{w|complex number}}s can be thought of as pairs <math>(a,\ b)\in\mathbb{R}\times\mathbb{R}</math> of real numbers with rules for addition and multiplication.

: <math>(a,\ b) + (c,\ d) = (a+c,\ b+d)</math>

: <math>(a,\ b) \cdot (c,\ d) = (ac - bd,\ ad + bc)</math>

As such, they can be modelled as two-dimensional {{w|Euclidean vector|vectors}}, with an interesting rule for multiplication. The justification for this rule is to consider a complex number as an expression of the form <math>a+bi</math>, where <math>i^2 = -1</math>, i.e. ''i'' is the square root of negative 1. Applying the common rules of algebra and the definition of ''i'' yields rules for addition and multiplication above.

Regular two-dimensional vectors are pairs of values, with the same rule for addition, and no rule for multiplication.

The usual way to introduce complex numbers is by starting with ''i'' and deducing the rules for addition and multiplication, but Cueball is correct to say that some uses of complex numbers could be modelled with vectors alone, without consideration of the square root of a negative number.

The teacher, [[Miss Lenhart]], counters that to ignore the natural construction of the complex numbers would hide the relevance of the {{w|fundamental theorem of algebra}} (Every polynomial of degree ''n'' has exactly ''n'' roots, when counted according to multiplicity) and much of {{w|complex analysis}} (calculus with complex numbers; the study of analytic and meromorphic functions), but she also agrees that mathematicians are too cool for "regular vectors." Just because the complex numbers can be interpreted through vector space, however, that doesn't mean that they ''are'' just vectors, any more than being able to construct the natural numbers from set logic mean that natural numbers are ''really'' just sets.

In mathematics, a {{w|group (mathematics)|group}} is the pairing of a binary operation (say, multiplication) with the set of numbers that operation can be used on (say, the real numbers), such that you can describe the properties of the operation by its corresponding group. An {{w|Abelian group}} is one where the operation is commutative, that is, where the terms of the operation can be exchanged: <math> a \cdot b = b \cdot a</math> The title text argues that the "link" between algebra and geometry in "algebreic [sic] geometry" and "geometric algebra" is the operation in an Abelian group, such that both of those fields are equivalent. Algebraic geometry and geometric algebra are mostly unrelated areas of study in mathematics. {{w|Algebraic geometry}} studies the properties of sets of zeros of polynomials. It runs relatively deep. Its tools were used for example in Andrew Wiles' celebrated proof of Fermat's Last Theorem. For its part, a {{w|geometric algebra| geometric algebra}} (a {{w|Clifford algebra| Clifford algebra}} with some specific properties) is a construct allowing one to do algebraic manipulation of geometric objects (e.g., vectors, planes, spheres, etc.) in an arbitrary space that has a resultant geometric interpretation (e.g., rotation, displacement, etc.). The algebra of quaternions, often used to handle rotations in 3D computer graphics, is an example of a geometric algebra, as is the algebra of complex numbers. {{w|Metabelian group|Meta-Abelian groups}} (often contracted to metabelian groups) is a class of groups that are not quite abelian, but close to being so.

Randall's joke in the mouseover text is a wordplay combining the concepts of (meta-)abelian groups and change in the order of word orders with the general idea of "meta".

This comic is similar to the earlier Miss Lenhart comic [[1724: Proofs]].

==Transcript==
:[Cueball (the student) is raising his hand and writing with his other hand. He is sitting down at a desk, which has a piece of paper on it.]
:Cueball: Does any of this really have to do with the square root of -1? Or do mathematicians just think they're too cool for regular vectors?

:[Miss Lenhart (the teacher) is standing in front of a whiteboard.]
:Miss Lenhart: Complex numbers aren't just vectors. They're a profound extension of real numbers, laying the foundation for the fundamental theorem of algebra and the entire field of complex analysis.

:[Miss Lenhart is standing slightly to the right in a blank frame.]
:Miss Lenhart: '''''And''''' we're too cool for regular vectors.
:Cueball (off-screen): I '''''knew''''' it!

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Miss Lenhart]]
[[Category:Math]]
[[Category:Analysis]]

1971: Personal Data

2018-03-23T20:13:18Z

141.101.77.236: /* Topics */ stocks

{{comic
| number = 1971
| date = March 23, 2018
| title = Personal Data
| image = personal_data.png
| titletext = Do I just leave money in my mailbox? How much? How much money do they need, anyway? I guess it probably depends how the economy is doing. If stocks go up, should I leave more money in my mailbox or less?
}}

==Explanation==
{{incomplete|Created by a typical xkcd Adult... so need more... Add explanation of what Stock, what personal data is and what the economy and tax is as well. Maybe a table? PLEASE. Do NOT delete this tag too soon.}}

This is another comic poking fun at adults who have trouble dealing with grown-up issues.

The comic starts with [[Cueball]] wondering what "{{w|personal data}}" is, saying he doesn't understand what it is, and it is an abstract concept. [[Ponytail]] follows by pointing out she doesn't understand what "{{w|Economy|the economy}}" is, and conjecturing that it is related to "{{w|Stock|stocks}}", although admitting that she also does not understand what stocks are. The punchline comes when [[White Hat]] says that he doesn't understand what "{{w|taxes}}" are and asks if he really has to pay them and to who. This surprises Cueball and Ponytail, who promptly advise him to learn about that one soon. The title text has White Hat asking another series of tax-related questions that adults are expected to know already, further compounding his troubles.

White Hat not knowing what taxes are indicates that he may not have paid his taxes in previous years, which would be alarming since tax evasion is punishable as a crime. Ponytail's remark that he should do this ideally in the next few weeks is referring to this year's US {{w|Tax Day (United States)|Tax Day}} which falls on April 17, 2018, less than four weeks after the release of this comic. So if you do not have your tax preparation under control, it is time to research how it works now.

This is not the first time [[Randall]] has made a comic about people having trouble understanding the US tax system in relation to an approaching tax day. Other instances include the title text of [[1805: Unpublished Discoveries]] from March the year before this comic, and this one from August 2015: [[1566: Board Game]].

==Topics==
This comic references several advanced topics that people commonly talk about, but may not actually understand well:

'''Personal data'''

Personal data is usually thought of as any information that pertains to a private person. But this definition is very vague and can encompass a huge variety of data ranging from very sensitive (Social Security number, bank account details, passwords) to less sensitive (first name, color of pet cat). Different people also have different ideas of what information is considered sensitive. For example, some may want eagerly to share the location of their weekend activity with the world, whereas others may prefer not to let everyone know their location.

Even though it is generally advised to keep personal data private and not to expose it to the public or to companies (especially online, e.g. Facebook and Google), not everyone agrees on the level of privacy that should be afforded to the data. Some hold the view that even innocent-looking personal data can be harvested and used for unsavory purposes (for example, a health insurance company can use social media posts about eating fast food as a cause to raise premiums, or a government can use cat pictures as evidence of pet ownership and demand license fees), and therefore all personal data should be strictly controlled. Others hold the view that sometimes it is worth exchanging some degree of privacy for other conveniences (for example, meeting friends by sharing their location info or getting cheaper prices from targeted advertising based on web browsing history).

Personal data breaches were in the news a few days before the publishing of this comic when the UK's Channel Four released an investigative documentary about political consulting firm Cambridge Analytica. Among the revelations of the documentary were that the company had used Facebook to not only harvest the personal data of users taking their polls, but the friends and family of those users, without their knowledge or consent. They used this information to attempt to influence both the 2016 United States elections and the UK's 'Brexit' vote. This sparked an ongoing discussion about the security of personal data and the role of social media in securing it.

Technological changes in the past few decades have made personal data much easier to collect, share, and analyze in bulk, raising new questions and concerns that have not been considered before. Even people who can define what data is personal to them may not realize the full extent of how others might use it, or how it impacts their lives.

'''The economy'''

The economy, at a basic level, is the circulation of money which enables productivity. For example, a bus driver might use their money to watch a movie, the movie producer might use their revenue (gathered from the bus driver and many others) to purchase editing software, the software maker might use their revenue (from the movie producer and others) to buy food, and the food producer might use that money to take a bus, thus returning the money back to the bus driver. The total amount of money has not changed, it merely circulated in a loop, but everyone in the loop received benefits and produced value in the form of goods or services.

The real world economy has much larger and more complex networks of buyers and producers compared to the toy example above, but nevertheless it works on the same principle. Many people correctly associate the economy with money (or stocks in Ponytail's case), but may not understand the full picture.

Circulation of money is critical to a healthy economy. In a recession, financial hardship causes people spend less money, which leads to fewer goods being produced, fewer jobs available, and people earning and spending even less money. That is why (somewhat counter-intuitively) governments need to spend ''more'' money during a recession in order to infuse money back into the economy and get it circulating again. The mint printing more money is also a planned, strategic move to cause inflation, which encourages people to spend their money now rather than save it for later because it will lose value over time. Again, getting people to spend their money is necessary to maintain the economy.

'''Stocks'''

Stocks in this context refers to companies listed on public stock exchanges, in which investors can buy and sell an economic stake, or share. Through pension funds, mutual funds and other investment vehicles, a large portion of the population of developed countries can therefore have an indirect stake in the success (or otherwise) of many of the businesses that make up a significant element of the economy (see above). An economy that is experiencing healthy growth would generally see the value of those businesses increase, and that is reflected in the value at which investors would be willing to buy and sell those shares. So a growing economy would tend to associated with rising stock prices.

'''Taxes'''

==Transcript==
:[Cueball is talking to Ponytail and White Hat. Both of them are looking at Cueball.]
:Cueball: Everyone keeps talking about "personal data." To be honest, I don't really know what it ''is''.
:Cueball: I mean, I understand the idea and know it's a thing I should protect. But it's so... abstract.

:[Close-up on Ponytail.]
:Ponytail: Yeah.
:Ponytail: It's like "the economy." I don't really know what the economy is, if we're getting specific. I know stocks going up is good. For people who own stocks, at least.
:Ponytail: Whatever "stocks" are.

:[White Hat responds holding his arms slightly out. Both Ponytail and Cueball are looking at him.]
:White Hat: Yeah, or taxes. Everyone talks about taxes. What '''''are''''' they? Do '''''I''''' have to pay them? And to who?
:Cueball: OK, wait, you definitely need to learn about that one.
:Ponytail: Yeah, ideally sometime in the next few weeks.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]