https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&feedformat=atom&user=71.169.189.201explain xkcd - User contributions [en]2026-07-10T07:26:44ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=599:_Apocalypse&diff=40790599: Apocalypse2013-06-15T17:30:14Z<p>71.169.189.201: /* Explanation */</p>
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<div>{{comic<br />
| number = 599<br />
| date = June 19, 2009<br />
| title = Apocalypse<br />
| image = apocalypse.png<br />
| titletext = I wonder if I still have time to go shoot a short film with Kevin Bacon.<br />
| imagesize =<br />
}}<br />
<br />
== Explanation ==<br />
According to Wikipedia, {{w|Paul Erdős}} (26 March 1913 – 20 September 1996) was a Hungarian mathematician who published more papers than any other mathematician in history, working with hundreds of collaborators.<br />
<br />
An in-joke developed among mathematicians called the {{w|Erdős number}}. By definition, Erdős has an Erdős number of 0. Everyone who has co-written a mathematical paper with Erdős has an Erdős number of 1. Everyone who collaborated with them (but not Erdős himself) is assigned an Erdős number of 2. In general, if ''k'' is the minimal Erdős number of all the people you've written papers with, your Erdős number is ''k'' + 1. The Erdős number is the length of the shortest "chain" from you to Erdős.<br />
<br />
Not everyone has an Erdős number, meaning that they don't have any chain linking them to Erdős. Most non-mathematicians do not have an Erdős number.<br />
<br />
In this comic, the apocalypse happens. [[Cueball]] quickly writes a math paper and gets everyone from the math dept. to sign it. Then he gets the resurrected Erdős to sign it. This way everyone from the math dept. has an Erdős number of 1.<br />
<br />
Paul Erdős described people who had stopped doing mathematics as "dead."<br />
<br />
The title text mentions a similar (and less esoteric) meme called {{w|Six degrees of Kevin Bacon}}. This time, the chain's center is actor {{w|Kevin Bacon}}, and the links are formed by two people appearing in the same movie.<br />
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==Transcript==<br />
:[Scene of meteors showering the earth.]<br />
<br />
:Beret Guy: The apocalypse! The skies burn, the seas turn to blood, and the dead walk the earth!<br />
<br />
:[Cueball and Beret Guy.]<br />
:Cueball: The dead what?<br />
:Beret Guy: Walk the earth!<br />
<br />
:[Cueball running.]<br />
:Cueball: I have to go.<br />
<br />
:[Cueball scribbling at a table. Mathematical symbols and equations are above Cueball's head.]<br />
:''Scribble scribble''<br />
<br />
:[Cueball running, paper in hand.]<br />
<br />
:[Cueball opening door labelled "Math dept."]<br />
:Cueball: The dead return!<br />
:Cueball: Everyone, quick, get your names on here!<br />
<br />
:[People lining up.]<br />
:Woman signing paper: At last!<br />
:Man in line: I hope there's still time!<br />
<br />
:[Cueball running.]<br />
<br />
:[Cueball at a cemetery.]<br />
:Rising dead: ''Hurrghhh''<br />
<br />
:[Cueball finds a man rising from his grave.]<br />
<br />
:Cueball: Paul Erdős?<br />
:Erdős: Yes?<br />
:Cueball: We need you to sign this.<br />
<br />
{{Comic discussion}}<br />
[[Category:Comics featuring Beret Guy]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics with color]]<br />
[[Category:Math]]</div>71.169.189.201