explain xkcd - User contributions [en]

Talk:2769: Overlapping Circles

2023-04-29T06:10:27Z

172.70.254.216: Venn diagrams *only* have the one defined shape

Incorrect. I’m sure there are set theorists who get excited about that shape who are not astronomers, and astronomers who get excited about that shape who are not set theorists, and people who get excited about it who are neither. [[Special:Contributions/162.158.91.35|162.158.91.35]] 23:16, 28 April 2023 (UTC)
:Hmmm, I'm not a set theorist, but I don't think that's what the Venn diagram is trying to say. My understanding is that both set theorists and astronomers get excited about that shape, not that only people who are both astronomers and set theorists would be excited. [[User:Alcatraz ii|Alcatraz ii]] ([[User talk:Alcatraz ii|talk]]) 23:20, 28 April 2023 (UTC)
::I agree with Alcatraz ii. The original poster has a point that there are people who agree neither set theorists nor astronomers and get excited about this shape, but a Venn diagram does not imply that the people in the overlapping section are both set theorists and astronomers. [[User:Python|Python]] ([[User talk:Python|talk]]) 23:31, 28 April 2023 (UTC)Python
:Actually, it does. That's what overlaps in a Venn diagram mean, it's the set of entities that satisfy both conditions. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 02:25, 29 April 2023 (UTC)
::You're right. People who get excited about the diagram would be the union of the two sets, not intersection. Unless Randall is saying that only astronomers who are also set theorists are so enamored of the two diagrams that they get excited about it. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 04:52, 29 April 2023 (UTC)

On title text: I'm pretty sure that if two sets are represented by a single circle rater than two, it's no longer a Venn diagram but merely an Euler diagram. [[Special:Contributions/172.71.94.3|172.71.94.3]] 00:22, 29 April 2023 (UTC)
:A single circle can be either. Two (or more) intersecting circles/loops-of-whatever-shape can be either, but might disqualify themselves from being strict Venns if they do not exhibit exactly 2ⁿ different sub-regions from ''n'' basic standalone partitioning regions. (This includes the whole surrounding one, not within any single partition, which purists might deem needs an "everything else"-sort of label/manifest, if you're putting things inside other parts, but that maybe can be taken as read.)
:You can't but help having 2 regions (inside and outside) from an ''n''=1 circle. (And one region from being constrained by ''n''=0 partitioning boundaries!)
:It's once you have two or more that you start to get the Euler-not-Ven exceptions, like [[1180: Virus Venn Diagram|entirely unintersecting groups]] (notably misnamed, by this comic) or [[2721: Euler Diagrams|only partially supporting all groups]] (misnamed by Cueball, in-Universe), unless you make effort to have some (singly unique) areas covering [[2122: Size Venn Diagram|all combinations of all options]].
:But an annular eclipse probably doesn't count. In 9ne, you cannot see/infer a point upon the Moon's surface that is not also where the Sun 'is' – albeit obscured – though you do see bits of Sun-surface that have no Moon coincident to your view (during the phase of maximum coverage). One assumes that non-annular eclipses (or hypo-annular ones, where the Sun's bodily 'cross-section' is at a minimum compared to the Moon's) are just onzerved as perfect fits. And this must exclude the upper-atmosphere/corona of the Sun (the Bailey's Beads/Diamond Ring effects being the limiting factors), so that you theoretically have a single circle and announce to yourself that all that you see within that is on a sightline which intersects both Sun and Moon, and all sightlines outwith that circle intersect neither. No room in your defining diagram/worldview/skyview for one XOR the other (like having a region for "red cars", but handling red non-cars and non-red cars (and all things that are neither red nor a car) as possibilities. [[Special:Contributions/141.101.98.9|141.101.98.9]] 03:47, 29 April 2023 (UTC)
::The way I’ve heard it (though I can’t remember where), it’s a Venn diagram iff it’s a Euler diagram with two congruent circles that overlap without regard for proportion; ''any'' other type of Euler diagram is not a Venn diagram. I’m not sure where to find an authoritative definition though. —[[Special:Contributions/172.70.254.216|172.70.254.216]] 06:10, 29 April 2023 (UTC)

The shape formed by the intersection of two circles is called a lens. Lenses are also of interest to astronomers for telescope manufacture. A lens shape causes spherical aberation when used as an optical element, leading to the use of aspheric lenses and mirrors on higher quality telescopes. [[User:Quantum7|Quantum7]] ([[User talk:Quantum7|talk]]) 05:25, 29 April 2023 (UTC)

2766: Helium Reserve

2023-04-22T16:37:38Z

172.70.254.216: /* Explanation */ Randall implies. We infer

{{comic
| number = 2766
| date = April 21, 2023
| title = Helium Reserve
| image = helium_reserve_2x.png
| imagesize = 347x253px
| noexpand = true
| titletext = The government has been trying to sell off the Federal Helium Reserve for a few years now, but the sale has been on hold while they try to figure out how to explain this situation to buyers.
}}

==Explanation==
{{incomplete|Created by DONALD DUCK - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The {{w|National Helium Reserve|Strategic National Helium Reserve}} is a reserve of helium in the United States, which holds more than 1 billion cubic meters of helium. Apparently, in this comic, [[Randall]] was hired to manage the reserve, and due to the fact that the caption says that he can not explain anything out loud, it can be inferred that [[Randall]] used all of it by repeatedly inhaling the helium supply, so speaking would instantly give away where the helium has gone since the helium would make his voice squeaky.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[An officer is talking to Cueball. There is a "National Strategic Helium Reserve" building in the background.]
:Officer: You were in charge of guarding the national helium reserve. So where did it go?!

:[Caption below the panel:]
:Unfortunately, there's no good way for me to answer this question out loud.

{{comic discussion}}

[[Category:Comics featuring Cueball]]

Talk:2740: Square Packing

2023-02-21T13:08:09Z

172.70.254.216:

I suspect Randall saw the same social media post that I did (or maybe a repost of the same social media post, who knows or cares). I don't really want to make an explanation, but anyone who does, here's a link to a bunch of square packing findings... of course, no hydraulic press allowed for these packings. https://erich-friedman.github.io/packing/squinsqu/ [[User:Tsumikiminiwa|Tsumikiminiwa]] ([[User talk:Tsumikiminiwa|talk]]) 22:07, 20 February 2023 (UTC)

:Yeah, this was on r/mathmemes the other day. [[Special:Contributions/172.64.238.48|172.64.238.48]] 00:03, 21 February 2023 (UTC)

Welcome to the Hydraulic Press Channel. Today we have a set of squares that are usually used in packing problems. You are supposed to fit them into other squares by arranging them. But I think we can get them to fit easier if we put them on the press, and just try to make them smaller. We are going to start with one square, and see how much smaller we can make this. And here we go.

The post where I saw this said: “God is dead, and what killed him was learning [the similarly inelegant-appearing n=17 solution].” [[Special:Contributions/172.70.254.216|172.70.254.216]] 13:08, 21 February 2023 (UTC)